21568464 has 40 divisors (see below), whose sum is σ = 61910720. Its totient is φ = 7189344.

The previous prime is 21568433. The next prime is 21568471. The reversal of 21568464 is 46486512.

It is a hoax number, since the sum of its digits (36) coincides with the sum of the digits of its distinct prime factors.

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

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 24532 + ... + 25395.

It is an arithmetic number, because the mean of its divisors is an integer number (1547768).

Almost surely, 2^21568464 is an apocalyptic number.

21568464 is a gapful number since it is divisible by the number (24) formed by its first and last digit.

It is an amenable number.

21568464 is an abundant number, since it is smaller than the sum of its proper divisors (40342256).

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

21568464 is a wasteful number, since it uses less digits than its factorization.

21568464 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 49944 (or 49932 counting only the distinct ones).

The product of its digits is 46080, while the sum is 36.

The square root of 21568464 is about 4644.1860427851. The cubic root of 21568464 is about 278.3597296092.

The spelling of 21568464 in words is "twenty-one million, five hundred sixty-eight thousand, four hundred sixty-four".