21535332 has 144 divisors (see below), whose sum is σ = 65423232. Its totient is φ = 5391360.

The previous prime is 21535309. The next prime is 21535351. The reversal of 21535332 is 23353512.

It is a happy number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 525232 + ... + 525272.

It is an arithmetic number, because the mean of its divisors is an integer number (454328).

Almost surely, 2^21535332 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 21535332, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (32711616).

21535332 is an abundant number, since it is smaller than the sum of its proper divisors (43887900).

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

21535332 is a wasteful number, since it uses less digits than its factorization.

21535332 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 118 (or 103 counting only the distinct ones).

The product of its digits is 2700, while the sum is 24.

The square root of 21535332 is about 4640.6176313073. The cubic root of 21535332 is about 278.2171241679.

Adding to 21535332 its reverse (23353512), we get a palindrome (44888844).

The spelling of 21535332 in words is "twenty-one million, five hundred thirty-five thousand, three hundred thirty-two".