66555651660 has 24 divisors (see below), whose sum is σ = 186355824816. Its totient is φ = 17748173760.

The previous prime is 66555651647. The next prime is 66555651667. The reversal of 66555651660 is 6615655566.

It is not an unprimeable number, because it can be changed into a prime (66555651667) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 554630371 + ... + 554630490.

It is an arithmetic number, because the mean of its divisors is an integer number (7764826034).

Almost surely, 2^66555651660 is an apocalyptic number.

66555651660 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

66555651660 is an abundant number, since it is smaller than the sum of its proper divisors (119800173156).

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

66555651660 is a wasteful number, since it uses less digits than its factorization.

66555651660 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1109260873 (or 1109260871 counting only the distinct ones).

The product of its (nonzero) digits is 4860000, while the sum is 51.

The spelling of 66555651660 in words is "sixty-six billion, five hundred fifty-five million, six hundred fifty-one thousand, six hundred sixty".