21132 has 18 divisors (see below), whose sum is σ = 53508. Its totient is φ = 7032.

The previous prime is 21121. The next prime is 21139. The reversal of 21132 is 23112.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (18).

It is a super-2 number, since 2×21132² = 893122848, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (9).

It is a nude number because it is divisible by every one of its digits and also a Zuckerman number because it is divisible by the product of its digits.

It is an Ulam number.

It is not an unprimeable number, because it can be changed into a prime (21139) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 258 + ... + 329.

2²¹¹³² is an apocalyptic number.

It is an amenable number.

21132 is an abundant number, since it is smaller than the sum of its proper divisors (32376).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21132 is a wasteful number, since it uses less digits than its factorization.

21132 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 597 (or 592 counting only the distinct ones).

The product of its digits is 12, while the sum is 9.

The square root of 21132 is about 145.3684972750. The cubic root of 21132 is about 27.6469270980.

Adding to 21132 its reverse (23112), we get a palindrome (44244).

It can be divided in two parts, 211 and 32, that added together give a 5-th power (243 = 3⁵).

The spelling of 21132 in words is "twenty-one thousand, one hundred thirty-two".