21368856 has 32 divisors (see below), whose sum is σ = 54331200. Its totient is φ = 7001760.

The previous prime is 21368843. The next prime is 21368857. The reversal of 21368856 is 65886312.

It is a happy number.

It is a Smith number, since the sum of its digits (39) coincides with the sum of the digits of its prime factors.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21368857) 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 7 ways as a sum of consecutive naturals, for example, 6130 + ... + 8961.

It is an arithmetic number, because the mean of its divisors is an integer number (1697850).

Almost surely, 2^21368856 is an apocalyptic number.

It is an amenable number.

21368856 is an abundant number, since it is smaller than the sum of its proper divisors (32962344).

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

21368856 is a wasteful number, since it uses less digits than its factorization.

21368856 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 15159 (or 15155 counting only the distinct ones).

The product of its digits is 69120, while the sum is 39.

The square root of 21368856 is about 4622.6459955311. The cubic root of 21368856 is about 277.4983621363.

The spelling of 21368856 in words is "twenty-one million, three hundred sixty-eight thousand, eight hundred fifty-six".