668599680 has 128 divisors (see below), whose sum is σ = 2435662080. Its totient is φ = 152819712.

The previous prime is 668599667. The next prime is 668599703. The reversal of 668599680 is 86995866.

It is a tau number, because it is divible by the number of its divisors (128).

It is a super-2 number, since 2×668599680² = 894051064192204800, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 668599680.

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, 11434 + ... + 38313.

It is an arithmetic number, because the mean of its divisors is an integer number (19028610).

Almost surely, 2^668599680 is an apocalyptic number.

668599680 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

668599680 is an abundant number, since it is smaller than the sum of its proper divisors (1767062400).

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

668599680 is a wasteful number, since it uses less digits than its factorization.

668599680 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 49776 (or 49764 counting only the distinct ones).

The product of its (nonzero) digits is 5598720, while the sum is 57.

The square root of 668599680 is about 25857.2945220493. The cubic root of 668599680 is about 874.4239713491.

The spelling of 668599680 in words is "six hundred sixty-eight million, five hundred ninety-nine thousand, six hundred eighty".