665844580 has 12 divisors (see below), whose sum is σ = 1398273660. Its totient is φ = 266337824.

The previous prime is 665844547. The next prime is 665844583. The reversal of 665844580 is 85448566.

It can be written as a sum of positive squares in 2 ways, for example, as 299428416 + 366416164 = 17304^2 + 19142^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 665844580.

It is not an unprimeable number, because it can be changed into a prime (665844583) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 16646095 + ... + 16646134.

It is an arithmetic number, because the mean of its divisors is an integer number (116522805).

Almost surely, 2^665844580 is an apocalyptic number.

It is an amenable number.

665844580 is an abundant number, since it is smaller than the sum of its proper divisors (732429080).

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

665844580 is a wasteful number, since it uses less digits than its factorization.

665844580 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 33292238 (or 33292236 counting only the distinct ones).

The product of its (nonzero) digits is 921600, while the sum is 46.

The square root of 665844580 is about 25803.9644240958. The cubic root of 665844580 is about 873.2212376117.

The spelling of 665844580 in words is "six hundred sixty-five million, eight hundred forty-four thousand, five hundred eighty".