657639968 has 48 divisors (see below), whose sum is σ = 1373428224. Its totient is φ = 308904960.

The previous prime is 657639929. The next prime is 657640001. The reversal of 657639968 is 869936756.

It is a super-2 number, since 2×657639968² = 864980655022082048, which contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 494921 + ... + 496247.

It is an arithmetic number, because the mean of its divisors is an integer number (28613088).

Almost surely, 2^657639968 is an apocalyptic number.

657639968 is a gapful number since it is divisible by the number (68) 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 657639968, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (686714112).

657639968 is an abundant number, since it is smaller than the sum of its proper divisors (715788256).

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

657639968 is a wasteful number, since it uses less digits than its factorization.

657639968 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2265 (or 2257 counting only the distinct ones).

The product of its digits is 14696640, while the sum is 59.

The square root of 657639968 is about 25644.4919622129. The cubic root of 657639968 is about 869.6197607329.

The spelling of 657639968 in words is "six hundred fifty-seven million, six hundred thirty-nine thousand, nine hundred sixty-eight".