21323232 has 108 divisors (see below), whose sum is σ = 70584696. Its totient is φ = 6088320.

The previous prime is 21323209. The next prime is 21323261. The reversal of 21323232 is 23232312.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a nude number because it is divisible by every one of its digits.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 13357 + ... + 14867.

It is an arithmetic number, because the mean of its divisors is an integer number (653562).

Almost surely, 2^21323232 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21323232, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (35292348).

21323232 is an abundant number, since it is smaller than the sum of its proper divisors (49261464).

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

21323232 is a wasteful number, since it uses less digits than its factorization.

21323232 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1541 (or 1523 counting only the distinct ones).

The product of its digits is 432, while the sum is 18.

The square root of 21323232 is about 4617.7085226333. The cubic root of 21323232 is about 277.3007286210.

Adding to 21323232 its reverse (23232312), we get a palindrome (44555544).

The spelling of 21323232 in words is "twenty-one million, three hundred twenty-three thousand, two hundred thirty-two".