66564864 has 108 divisors (see below), whose sum is σ = 194188176. Its totient is φ = 21927936.

The previous prime is 66564851. The next prime is 66564871. The reversal of 66564864 is 46846566.

66564864 is a `hidden beast` number, since 6 + 6 + 564 + 86 + 4 = 666.

It is a super-2 number, since 2×66564864² = 8861762238676992, which contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 384682 + ... + 384854.

Almost surely, 2^66564864 is an apocalyptic number.

66564864 is a gapful number since it is divisible by the number (64) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 66564864, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (97094088).

66564864 is an abundant number, since it is smaller than the sum of its proper divisors (127623312).

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

66564864 is a wasteful number, since it uses less digits than its factorization.

66564864 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 362 (or 345 counting only the distinct ones).

The product of its digits is 829440, while the sum is 45.

The square root of 66564864 is about 8158.7293128281. The cubic root of 66564864 is about 405.2736330972.

The spelling of 66564864 in words is "sixty-six million, five hundred sixty-four thousand, eight hundred sixty-four".