166650550621 has 4 divisors (see below), whose sum is σ = 166651777600. Its totient is φ = 166649323644.

The previous prime is 166650550613. The next prime is 166650550637. The reversal of 166650550621 is 126055056661.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 166650550621 - 2³ = 166650550613 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (166650550321) 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, 380181 + ... + 691258.

It is an arithmetic number, because the mean of its divisors is an integer number (41662944400).

Almost surely, 2^166650550621 is an apocalyptic number.

It is an amenable number.

166650550621 is a deficient number, since it is larger than the sum of its proper divisors (1226979).

166650550621 is a wasteful number, since it uses less digits than its factorization.

166650550621 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1226978.

The product of its (nonzero) digits is 324000, while the sum is 43.

The spelling of 166650550621 in words is "one hundred sixty-six billion, six hundred fifty million, five hundred fifty thousand, six hundred twenty-one".