166638788 has 6 divisors (see below), whose sum is σ = 291617886. Its totient is φ = 83319392.

The previous prime is 166638781. The next prime is 166638799. The reversal of 166638788 is 887836661.

It can be written as a sum of positive squares in only one way, i.e., 151831684 + 14807104 = 12322^2 + 3848^2 .

It is a super-2 number, since 2×166638788² = 55536971332217888, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (166638781) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 20829845 + ... + 20829852.

It is an arithmetic number, because the mean of its divisors is an integer number (48602981).

Almost surely, 2^166638788 is an apocalyptic number.

It is an amenable number.

166638788 is a deficient number, since it is larger than the sum of its proper divisors (124979098).

166638788 is a wasteful number, since it uses less digits than its factorization.

166638788 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 41659701 (or 41659699 counting only the distinct ones).

The product of its digits is 2322432, while the sum is 53.

The square root of 166638788 is about 12908.8647060847. The cubic root of 166638788 is about 550.2905219950.

The spelling of 166638788 in words is "one hundred sixty-six million, six hundred thirty-eight thousand, seven hundred eighty-eight".