21907432 has 16 divisors (see below), whose sum is σ = 41184900. Its totient is φ = 10924800.

The previous prime is 21907429. The next prime is 21907433. The reversal of 21907432 is 23470912.

It can be written as a sum of positive squares in 2 ways, for example, as 19131876 + 2775556 = 4374^2 + 1666^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 21907432.

It is not an unprimeable number, because it can be changed into a prime (21907433) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 207 + ... + 6622.

Almost surely, 2^21907432 is an apocalyptic number.

It is an amenable number.

21907432 is a deficient number, since it is larger than the sum of its proper divisors (19277468).

21907432 is a wasteful number, since it uses less digits than its factorization.

21907432 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7236 (or 7232 counting only the distinct ones).

The product of its (nonzero) digits is 3024, while the sum is 28.

The square root of 21907432 is about 4680.5375759628. The cubic root of 21907432 is about 279.8103818222.

The spelling of 21907432 in words is "twenty-one million, nine hundred seven thousand, four hundred thirty-two".