665055872 has 64 divisors (see below), whose sum is σ = 1453946760. Its totient is φ = 301117440.

The previous prime is 665055821. The next prime is 665055887. The reversal of 665055872 is 278550566.

It can be written as a sum of positive squares in 4 ways, for example, as 392673856 + 272382016 = 19816^2 + 16504^2 .

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

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, 84422 + ... + 91962.

Almost surely, 2^665055872 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 665055872, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (726973380).

665055872 is an abundant number, since it is smaller than the sum of its proper divisors (788890888).

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

665055872 is a wasteful number, since it uses less digits than its factorization.

665055872 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7621 (or 7609 counting only the distinct ones).

The product of its (nonzero) digits is 504000, while the sum is 44.

The square root of 665055872 is about 25788.6772053163. The cubic root of 665055872 is about 872.8763179367.

The spelling of 665055872 in words is "six hundred sixty-five million, fifty-five thousand, eight hundred seventy-two".