665161620 has 48 divisors (see below), whose sum is σ = 1864383360. Its totient is φ = 177192576.

The previous prime is 665161597. The next prime is 665161631. The reversal of 665161620 is 26161566.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 58566 + ... + 68994.

It is an arithmetic number, because the mean of its divisors is an integer number (38841320).

Almost surely, 2^665161620 is an apocalyptic number.

665161620 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

665161620 is an abundant number, since it is smaller than the sum of its proper divisors (1199221740).

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

665161620 is a wasteful number, since it uses less digits than its factorization.

665161620 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11504 (or 11502 counting only the distinct ones).

The product of its (nonzero) digits is 12960, while the sum is 33.

The square root of 665161620 is about 25790.7274034681. The cubic root of 665161620 is about 872.9225797306.

The spelling of 665161620 in words is "six hundred sixty-five million, one hundred sixty-one thousand, six hundred twenty".