665166020 has 24 divisors (see below), whose sum is σ = 1434602904. Its totient is φ = 258875136.

The previous prime is 665165939. The next prime is 665166031. The reversal of 665166020 is 20661566.

It can be written as a sum of positive squares in 4 ways, for example, as 426339904 + 238826116 = 20648^2 + 15454^2 .

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 448697 + ... + 450176.

It is an arithmetic number, because the mean of its divisors is an integer number (59775121).

Almost surely, 2^665166020 is an apocalyptic number.

It is an amenable number.

665166020 is an abundant number, since it is smaller than the sum of its proper divisors (769436884).

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

665166020 is a wasteful number, since it uses less digits than its factorization.

665166020 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 898919 (or 898917 counting only the distinct ones).

The product of its (nonzero) digits is 12960, while the sum is 32.

The square root of 665166020 is about 25790.8127053026. The cubic root of 665166020 is about 872.9245045013.

The spelling of 665166020 in words is "six hundred sixty-five million, one hundred sixty-six thousand, twenty".