21386256 has 40 divisors (see below), whose sum is σ = 56600544. Its totient is φ = 6954240.

The previous prime is 21386243. The next prime is 21386257. The reversal of 21386256 is 65268312.

It is not an unprimeable number, because it can be changed into a prime (21386257) 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, 3466 + ... + 7401.

Almost surely, 2^21386256 is an apocalyptic number.

It is an amenable number.

21386256 is an abundant number, since it is smaller than the sum of its proper divisors (35214288).

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

21386256 is a wasteful number, since it uses less digits than its factorization.

21386256 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10919 (or 10913 counting only the distinct ones).

The product of its digits is 17280, while the sum is 33.

The square root of 21386256 is about 4624.5276515553. The cubic root of 21386256 is about 277.5736611530.

The spelling of 21386256 in words is "twenty-one million, three hundred eighty-six thousand, two hundred fifty-six".