166386561 has 16 divisors (see below), whose sum is σ = 245084160. Its totient is φ = 99562320.

The previous prime is 166386551. The next prime is 166386587. The reversal of 166386561 is 165683661.

It is not a de Polignac number, because 166386561 - 2⁷ = 166386433 is a prime.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (166386551) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 29305 + ... + 34518.

It is an arithmetic number, because the mean of its divisors is an integer number (15317760).

Almost surely, 2^166386561 is an apocalyptic number.

166386561 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

166386561 is a deficient number, since it is larger than the sum of its proper divisors (78697599).

166386561 is a wasteful number, since it uses less digits than its factorization.

166386561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 63916.

The product of its digits is 155520, while the sum is 42.

The square root of 166386561 is about 12899.0914796353. The cubic root of 166386561 is about 550.0127390989.

The spelling of 166386561 in words is "one hundred sixty-six million, three hundred eighty-six thousand, five hundred sixty-one".