18231977156 has 6 divisors (see below), whose sum is σ = 31905960030. Its totient is φ = 9115988576.

The previous prime is 18231977149. The next prime is 18231977213. The reversal of 18231977156 is 65177913281.

It is a happy number.

It can be written as a sum of positive squares in only one way, i.e., 18229320256 + 2656900 = 135016^2 + 1630^2 .

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2278997141 + ... + 2278997148.

It is an arithmetic number, because the mean of its divisors is an integer number (5317660005).

Almost surely, 2^18231977156 is an apocalyptic number.

It is an amenable number.

18231977156 is a deficient number, since it is larger than the sum of its proper divisors (13673982874).

18231977156 is a wasteful number, since it uses less digits than its factorization.

18231977156 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4557994293 (or 4557994291 counting only the distinct ones).

The product of its digits is 635040, while the sum is 50.

The spelling of 18231977156 in words is "eighteen billion, two hundred thirty-one million, nine hundred seventy-seven thousand, one hundred fifty-six".