15840818138 has 16 divisors (see below), whose sum is σ = 24357704616. Its totient is φ = 7721852160.

The previous prime is 15840818057. The next prime is 15840818143. The reversal of 15840818138 is 83181804851.

It can be written as a sum of positive squares in 4 ways, for example, as 14628176809 + 1212641329 = 120947^2 + 34823^2 .

It is a junction number, because it is equal to n+sod(n) for n = 15840818092 and 15840818101.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 52670 + ... + 185622.

Almost surely, 2^15840818138 is an apocalyptic number.

15840818138 is a deficient number, since it is larger than the sum of its proper divisors (8516886478).

15840818138 is a wasteful number, since it uses less digits than its factorization.

15840818138 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 134449.

The product of its (nonzero) digits is 245760, while the sum is 47.

The spelling of 15840818138 in words is "fifteen billion, eight hundred forty million, eight hundred eighteen thousand, one hundred thirty-eight".