668920320 has 120 divisors (see below), whose sum is σ = 2316738996. Its totient is φ = 178372608.

The previous prime is 668920319. The next prime is 668920321. The reversal of 668920320 is 23029866.

668920320 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is an interprime number because it is at equal distance from previous prime (668920319) and next prime (668920321).

It can be written as a sum of positive squares in 2 ways, for example, as 654541056 + 14379264 = 25584^2 + 3792^2 .

It is a tau number, because it is divible by the number of its divisors (120).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is not an unprimeable number, because it can be changed into a prime (668920321) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 8524 + ... + 37556.

Almost surely, 2^668920320 is an apocalyptic number.

668920320 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 668920320, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1158369498).

668920320 is an abundant number, since it is smaller than the sum of its proper divisors (1647818676).

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

668920320 is a wasteful number, since it uses less digits than its factorization.

668920320 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 29062 (or 29043 counting only the distinct ones).

The product of its (nonzero) digits is 31104, while the sum is 36.

The square root of 668920320 is about 25863.4939635000. The cubic root of 668920320 is about 874.5637313593.

The spelling of 668920320 in words is "six hundred sixty-eight million, nine hundred twenty thousand, three hundred twenty".