166557666 has 32 divisors (see below), whose sum is σ = 364953600. Its totient is φ = 50256080.

The previous prime is 166557659. The next prime is 166557673. The reversal of 166557666 is 666755661.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (166557659) and next prime (166557673).

It is a super-2 number, since 2×166557666² = 55482912206735112, which contains 22 as substring.

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, 10495 + ... + 21053.

It is an arithmetic number, because the mean of its divisors is an integer number (11404800).

Almost surely, 2^166557666 is an apocalyptic number.

166557666 is an abundant number, since it is smaller than the sum of its proper divisors (198395934).

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

166557666 is a wasteful number, since it uses less digits than its factorization.

166557666 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10814.

The product of its digits is 1360800, while the sum is 48.

The square root of 166557666 is about 12905.7222192328. The cubic root of 166557666 is about 550.2012112287.

The spelling of 166557666 in words is "one hundred sixty-six million, five hundred fifty-seven thousand, six hundred sixty-six".