21256732 has 24 divisors (see below), whose sum is σ = 45015264. Its totient is φ = 8573952.

The previous prime is 21256721. The next prime is 21256733. The reversal of 21256732 is 23765212.

It is a Harshad number since it is a multiple of its sum of digits (28).

It is a self number, because there is not a number n which added to its sum of digits gives 21256732.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21256733) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 21853 + ... + 22804.

It is an arithmetic number, because the mean of its divisors is an integer number (1875636).

Almost surely, 2^21256732 is an apocalyptic number.

It is an amenable number.

21256732 is an abundant number, since it is smaller than the sum of its proper divisors (23758532).

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

21256732 is a wasteful number, since it uses less digits than its factorization.

21256732 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 44685 (or 44683 counting only the distinct ones).

The product of its digits is 5040, while the sum is 28.

The square root of 21256732 is about 4610.5023587457. The cubic root of 21256732 is about 277.0121591451.

The spelling of 21256732 in words is "twenty-one million, two hundred fifty-six thousand, seven hundred thirty-two".