diff --git a/index.js b/index.js
index 6d80316..7ee3d33 100644
--- a/index.js
+++ b/index.js
@@ -8,6 +8,19 @@ const LEADING_SEPARATORS = new RegExp('^' + SEPARATORS.source);
 const SEPARATORS_AND_IDENTIFIER = new RegExp(SEPARATORS.source + IDENTIFIER.source, 'gu');
 const NUMBERS_AND_IDENTIFIER = new RegExp('\\d+' + IDENTIFIER.source, 'gu');
 
+const applyCasingExpectAfterNumber = (string, applyCase) => {
+	let result = '';
+	for (let i = 0; i < string.length; i++) {
+		const currentChar = string[i];
+		const previousChar = string[i - 1];
+
+		const previousCharIsNumber = !Number.isNaN(Number(previousChar));
+		result += i > 0 && previousCharIsNumber ? currentChar : applyCase(currentChar);
+	}
+
+	return result;
+};
+
 const preserveCamelCase = (string, toLowerCase, toUpperCase, preserveConsecutiveUppercase) => {
 	let isLastCharLower = false;
 	let isLastCharUpper = false;
@@ -77,12 +90,12 @@ export default function camelCase(input, options) {
 	}
 
 	const toLowerCase = options.locale === false
-		? string => string.toLowerCase()
-		: string => string.toLocaleLowerCase(options.locale);
+		? string => applyCasingExpectAfterNumber(string, char => char.toLowerCase())
+		: string => applyCasingExpectAfterNumber(string, char => char.toLocaleLowerCase(options.locale));
 
 	const toUpperCase = options.locale === false
-		? string => string.toUpperCase()
-		: string => string.toLocaleUpperCase(options.locale);
+		? string => applyCasingExpectAfterNumber(string, char => char.toUpperCase())
+		: string => applyCasingExpectAfterNumber(string, char => char.toLocaleUpperCase(options.locale));
 
 	if (input.length === 1) {
 		if (SEPARATORS.test(input)) {
diff --git a/package.json b/package.json
index b62c0a6..094ee13 100644
--- a/package.json
+++ b/package.json
@@ -42,6 +42,6 @@
 	"devDependencies": {
 		"ava": "^4.3.0",
 		"tsd": "^0.20.0",
-		"xo": "^0.49.0"
+		"xo": "^0.54.2"
 	}
 }
diff --git a/test.js b/test.js
index 306b437..2c7e73c 100644
--- a/test.js
+++ b/test.js
@@ -60,13 +60,13 @@ test('camelCase', t => {
 	t.is(camelCase('A::a'), 'a::a');
 	t.is(camelCase('Hello1World'), 'hello1World');
 	t.is(camelCase('Hello11World'), 'hello11World');
-	t.is(camelCase('hello1world'), 'hello1World');
-	t.is(camelCase('Hello1World11foo'), 'hello1World11Foo');
+	t.is(camelCase('hello1world'), 'hello1world');
+	t.is(camelCase('Hello1World11foo'), 'hello1World11foo');
 	t.is(camelCase('Hello1'), 'hello1');
 	t.is(camelCase('hello1'), 'hello1');
 	t.is(camelCase('1Hello'), '1Hello');
-	t.is(camelCase('1hello'), '1Hello');
-	t.is(camelCase('h2w'), 'h2W');
+	t.is(camelCase('1hello'), '1hello');
+	t.is(camelCase('h2w'), 'h2w');
 	t.is(camelCase('розовый_пушистый-единороги'), 'розовыйПушистыйЕдинороги');
 	t.is(camelCase('розовый_пушистый-единороги'), 'розовыйПушистыйЕдинороги');
 	t.is(camelCase('РОЗОВЫЙ_ПУШИСТЫЙ-ЕДИНОРОГИ'), 'розовыйПушистыйЕдинороги');
@@ -126,11 +126,11 @@ test('camelCase with pascalCase option', t => {
 	t.is(camelCase('A::a', {pascalCase: true}), 'A::a');
 	t.is(camelCase('Hello1World', {pascalCase: true}), 'Hello1World');
 	t.is(camelCase('Hello11World', {pascalCase: true}), 'Hello11World');
-	t.is(camelCase('hello1world', {pascalCase: true}), 'Hello1World');
+	t.is(camelCase('hello1world', {pascalCase: true}), 'Hello1world');
 	t.is(camelCase('hello1World', {pascalCase: true}), 'Hello1World');
 	t.is(camelCase('hello1', {pascalCase: true}), 'Hello1');
 	t.is(camelCase('Hello1', {pascalCase: true}), 'Hello1');
-	t.is(camelCase('1hello', {pascalCase: true}), '1Hello');
+	t.is(camelCase('1hello', {pascalCase: true}), '1hello');
 	t.is(camelCase('1Hello', {pascalCase: true}), '1Hello');
 	t.is(camelCase('h1W', {pascalCase: true}), 'H1W');
 	t.is(camelCase('РозовыйПушистыйЕдинороги', {pascalCase: true}), 'РозовыйПушистыйЕдинороги');