21392856 has 32 divisors (see below), whose sum is σ = 59425200. Its totient is φ = 7130880.

The previous prime is 21392843. The next prime is 21392863. The reversal of 21392856 is 65829312.

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

It is a self number, because there is not a number n which added to its sum of digits gives 21392856.

It is a congruent number.

It is an unprimeable number.

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 7 ways as a sum of consecutive naturals, for example, 49305 + ... + 49736.

Almost surely, 2^21392856 is an apocalyptic number.

It is an amenable number.

21392856 is an abundant number, since it is smaller than the sum of its proper divisors (38032344).

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

21392856 is a wasteful number, since it uses less digits than its factorization.

21392856 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 99056 (or 99046 counting only the distinct ones).

The product of its digits is 25920, while the sum is 36.

The square root of 21392856 is about 4625.2411829006. The cubic root of 21392856 is about 277.6022121647.

The spelling of 21392856 in words is "twenty-one million, three hundred ninety-two thousand, eight hundred fifty-six".