66556566600656 has 80 divisors (see below), whose sum is σ = 145837567369728. Its totient is φ = 29151428812800.

The previous prime is 66556566600647. The next prime is 66556566600703. The reversal of 66556566600656 is 65600666565566.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 24906401 + ... + 27448896.

Almost surely, 2^{66556566600656} is an apocalyptic number.

It is an amenable number.

66556566600656 is an abundant number, since it is smaller than the sum of its proper divisors (79281000769072).

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

66556566600656 is a wasteful number, since it uses less digits than its factorization.

66556566600656 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 52355580 (or 52355574 counting only the distinct ones).

The product of its (nonzero) digits is 1049760000, while the sum is 68.

The spelling of 66556566600656 in words is "sixty-six trillion, five hundred fifty-six billion, five hundred sixty-six million, six hundred thousand, six hundred fifty-six".