66505664 has 28 divisors (see below), whose sum is σ = 136233408. Its totient is φ = 32179200.

The previous prime is 66505661. The next prime is 66505667. The reversal of 66505664 is 46650566.

It is an interprime number because it is at equal distance from previous prime (66505661) and next prime (66505667).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66505661) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 14777 + ... + 18744.

Almost surely, 2^66505664 is an apocalyptic number.

66505664 is a gapful number since it is divisible by the number (64) formed by its first and last digit.

It is an amenable number.

66505664 is an abundant number, since it is smaller than the sum of its proper divisors (69727744).

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

66505664 is a wasteful number, since it uses less digits than its factorization.

66505664 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 33564 (or 33554 counting only the distinct ones).

The product of its (nonzero) digits is 129600, while the sum is 38.

The square root of 66505664 is about 8155.1004898775. The cubic root of 66505664 is about 405.1534530016.

The spelling of 66505664 in words is "sixty-six million, five hundred five thousand, six hundred sixty-four".