668057984 has 64 divisors (see below), whose sum is σ = 1456131600. Its totient is φ = 302776320.

The previous prime is 668057983. The next prime is 668057987. The reversal of 668057984 is 489750866.

It is a tau number, because it is divible by the number of its divisors (64).

It is a super-2 number, since 2×668057984² = 892602939972288512, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (668057983) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 868352 + ... + 869120.

Almost surely, 2^668057984 is an apocalyptic number.

668057984 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 668057984, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (728065800).

668057984 is an abundant number, since it is smaller than the sum of its proper divisors (788073616).

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

668057984 is a wasteful number, since it uses less digits than its factorization.

668057984 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1411 (or 1399 counting only the distinct ones).

The product of its (nonzero) digits is 2903040, while the sum is 53.

The square root of 668057984 is about 25846.8176764568. The cubic root of 668057984 is about 874.1877562857.

The spelling of 668057984 in words is "six hundred sixty-eight million, fifty-seven thousand, nine hundred eighty-four".