21909852 has 36 divisors (see below), whose sum is σ = 57437016. Its totient is φ = 7302960.

The previous prime is 21909817. The next prime is 21909857. The reversal of 21909852 is 25890912.

It is a tau number, because it is divible by the number of its divisors (36).

It is a super-2 number, since 2×21909852² = 960083229323808, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21909857) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 10299 + ... + 12242.

Almost surely, 2^21909852 is an apocalyptic number.

It is an amenable number.

21909852 is an abundant number, since it is smaller than the sum of its proper divisors (35527164).

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

21909852 is a wasteful number, since it uses less digits than its factorization.

21909852 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 22560 (or 22546 counting only the distinct ones).

The product of its (nonzero) digits is 12960, while the sum is 36.

The square root of 21909852 is about 4680.7960861375. The cubic root of 21909852 is about 279.8206845084.

The spelling of 21909852 in words is "twenty-one million, nine hundred nine thousand, eight hundred fifty-two".