21564368 has 20 divisors (see below), whose sum is σ = 47749920. Its totient is φ = 9241824.

The previous prime is 21564353. The next prime is 21564379. The reversal of 21564368 is 86346512.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 96158 + ... + 96381.

It is an arithmetic number, because the mean of its divisors is an integer number (2387496).

Almost surely, 2^21564368 is an apocalyptic number.

21564368 is a gapful number since it is divisible by the number (28) formed by its first and last digit.

It is an amenable number.

21564368 is an abundant number, since it is smaller than the sum of its proper divisors (26185552).

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

21564368 is a wasteful number, since it uses less digits than its factorization.

21564368 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 192554 (or 192548 counting only the distinct ones).

The product of its digits is 34560, while the sum is 35.

The square root of 21564368 is about 4643.7450403742. The cubic root of 21564368 is about 278.3421076831.

The spelling of 21564368 in words is "twenty-one million, five hundred sixty-four thousand, three hundred sixty-eight".