811166638 has 4 divisors (see below), whose sum is σ = 1216749960. Its totient is φ = 405583318.

The previous prime is 811166623. The next prime is 811166659. The reversal of 811166638 is 836661118.

It is a semiprime because it is the product of two primes.

It is a Smith number, since the sum of its digits (40) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a self number, because there is not a number n which added to its sum of digits gives 811166638.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 202791658 + ... + 202791661.

It is an arithmetic number, because the mean of its divisors is an integer number (304187490).

Almost surely, 2^811166638 is an apocalyptic number.

811166638 is a deficient number, since it is larger than the sum of its proper divisors (405583322).

811166638 is a wasteful number, since it uses less digits than its factorization.

811166638 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 405583321.

The product of its digits is 41472, while the sum is 40.

The square root of 811166638 is about 28480.9873073249. The cubic root of 811166638 is about 932.6170698781.

The spelling of 811166638 in words is "eight hundred eleven million, one hundred sixty-six thousand, six hundred thirty-eight".