668644984 has 48 divisors (see below), whose sum is σ = 1465128000. Its totient is φ = 285239808.

The previous prime is 668644943. The next prime is 668645009. The reversal of 668644984 is 489446866.

It is a happy number.

It is a super-2 number, since 2×668644984² = 894172229256720512, which contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 83592 + ... + 91240.

It is an arithmetic number, because the mean of its divisors is an integer number (30523500).

Almost surely, 2^668644984 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 668644984, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (732564000).

668644984 is an abundant number, since it is smaller than the sum of its proper divisors (796483016).

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

668644984 is a wasteful number, since it uses less digits than its factorization.

668644984 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7892 (or 7881 counting only the distinct ones).

The product of its digits is 7962624, while the sum is 55.

The square root of 668644984 is about 25858.1705462703. The cubic root of 668644984 is about 874.4437210888.

The spelling of 668644984 in words is "six hundred sixty-eight million, six hundred forty-four thousand, nine hundred eighty-four".