166985091 has 128 divisors (see below), whose sum is σ = 331520000. Its totient is φ = 82301184.

The previous prime is 166985089. The next prime is 166985111. The reversal of 166985091 is 190589661.

It is not a de Polignac number, because 166985091 - 2¹ = 166985089 is a prime.

It is not an unprimeable number, because it can be changed into a prime (166985041) by changing a digit.

It is a polite number, since it can be written in 127 ways as a sum of consecutive naturals, for example, 2287431 + ... + 2287503.

It is an arithmetic number, because the mean of its divisors is an integer number (2590000).

Almost surely, 2^166985091 is an apocalyptic number.

166985091 is a deficient number, since it is larger than the sum of its proper divisors (164534909).

166985091 is a wasteful number, since it uses less digits than its factorization.

166985091 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 135 (or 115 counting only the distinct ones).

The product of its (nonzero) digits is 116640, while the sum is 45.

The square root of 166985091 is about 12922.2711239163. The cubic root of 166985091 is about 550.6714565162.

The spelling of 166985091 in words is "one hundred sixty-six million, nine hundred eighty-five thousand, ninety-one".