165800661 has 12 divisors (see below), whose sum is σ = 239381568. Its totient is φ = 102030864.

The previous prime is 165800641. The next prime is 165800671. The reversal of 165800661 is 166008561.

It is not a de Polignac number, because 165800661 - 2⁷ = 165800533 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (165800641) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 163005 + ... + 164018.

It is an arithmetic number, because the mean of its divisors is an integer number (19948464).

Almost surely, 2^165800661 is an apocalyptic number.

It is an amenable number.

165800661 is a deficient number, since it is larger than the sum of its proper divisors (73580907).

165800661 is a wasteful number, since it uses less digits than its factorization.

165800661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 327052 (or 327039 counting only the distinct ones).

The product of its (nonzero) digits is 8640, while the sum is 33.

The square root of 165800661 is about 12876.3605494720. The cubic root of 165800661 is about 549.3663899091.

The spelling of 165800661 in words is "one hundred sixty-five million, eight hundred thousand, six hundred sixty-one".