668815680 has 112 divisors (see below), whose sum is σ = 2286877824. Its totient is φ = 164628480.

The previous prime is 668815673. The next prime is 668815691. The reversal of 668815680 is 86518866.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (48).

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, 14316 + ... + 39275.

It is an arithmetic number, because the mean of its divisors is an integer number (20418552).

Almost surely, 2^668815680 is an apocalyptic number.

668815680 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

668815680 is an abundant number, since it is smaller than the sum of its proper divisors (1618062144).

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

668815680 is a wasteful number, since it uses less digits than its factorization.

668815680 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 53624 (or 53614 counting only the distinct ones).

The product of its (nonzero) digits is 552960, while the sum is 48.

The square root of 668815680 is about 25861.4709558447. The cubic root of 668815680 is about 874.5181259669.

The spelling of 668815680 in words is "six hundred sixty-eight million, eight hundred fifteen thousand, six hundred eighty".