21312774 has 32 divisors (see below), whose sum is σ = 54128640. Its totient is φ = 6089256.

The previous prime is 21312763. The next prime is 21312787. The reversal of 21312774 is 47721312.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 27814 + ... + 28569.

It is an arithmetic number, because the mean of its divisors is an integer number (1691520).

Almost surely, 2^21312774 is an apocalyptic number.

21312774 is an abundant number, since it is smaller than the sum of its proper divisors (32815866).

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

21312774 is a wasteful number, since it uses less digits than its factorization.

21312774 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 56401 (or 56395 counting only the distinct ones).

The product of its digits is 2352, while the sum is 27.

The square root of 21312774 is about 4616.5760039233. The cubic root of 21312774 is about 277.2553870696.

The spelling of 21312774 in words is "twenty-one million, three hundred twelve thousand, seven hundred seventy-four".