668513664 has 288 divisors, whose sum is σ = 2412577440. Its totient is φ = 176117760.

The previous prime is 668513639. The next prime is 668513687. The reversal of 668513664 is 466315866.

It is a tau number, because it is divible by the number of its divisors (288).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 733369 + ... + 734279.

It is an arithmetic number, because the mean of its divisors is an integer number (8377005).

Almost surely, 2^668513664 is an apocalyptic number.

668513664 is a gapful number since it is divisible by the number (64) 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 668513664, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1206288720).

668513664 is an abundant number, since it is smaller than the sum of its proper divisors (1744063776).

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

668513664 is a wasteful number, since it uses less digits than its factorization.

668513664 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 958 (or 936 counting only the distinct ones).

The product of its digits is 622080, while the sum is 45.

The square root of 668513664 is about 25855.6311854884. The cubic root of 668513664 is about 874.3864712424.

The spelling of 668513664 in words is "six hundred sixty-eight million, five hundred thirteen thousand, six hundred sixty-four".