21258372 has 12 divisors (see below), whose sum is σ = 49602896. Its totient is φ = 7086120.

The previous prime is 21258361. The next prime is 21258373. The reversal of 21258372 is 27385212.

It is a tau number, because it is divible by the number of its divisors (12).

It is a hoax number, since the sum of its digits (30) coincides with the sum of the digits of its distinct prime factors.

It is not an unprimeable number, because it can be changed into a prime (21258373) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 885754 + ... + 885777.

Almost surely, 2^21258372 is an apocalyptic number.

It is an amenable number.

21258372 is an abundant number, since it is smaller than the sum of its proper divisors (28344524).

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

21258372 is a wasteful number, since it uses less digits than its factorization.

21258372 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1771538 (or 1771536 counting only the distinct ones).

The product of its digits is 6720, while the sum is 30.

The square root of 21258372 is about 4610.6802101208. The cubic root of 21258372 is about 277.0192829786.

The spelling of 21258372 in words is "twenty-one million, two hundred fifty-eight thousand, three hundred seventy-two".