666581649600 has 168 divisors, whose sum is σ = 2214627381760. Its totient is φ = 175504942080.

The previous prime is 666581649571. The next prime is 666581649631. The reversal of 666581649600 is 6946185666.

It is a happy number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 499732 + ... + 1258131.

Almost surely, 2^666581649600 is an apocalyptic number.

666581649600 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

666581649600 is an abundant number, since it is smaller than the sum of its proper divisors (1548045732160).

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

666581649600 is a wasteful number, since it uses less digits than its factorization.

666581649600 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1757967 (or 1757952 counting only the distinct ones).

The product of its (nonzero) digits is 11197440, while the sum is 57.

The spelling of 666581649600 in words is "six hundred sixty-six billion, five hundred eighty-one million, six hundred forty-nine thousand, six hundred".