15825781138 has 16 divisors (see below), whose sum is σ = 23923238040. Its totient is φ = 7851580416.

The previous prime is 15825781121. The next prime is 15825781141. The reversal of 15825781138 is 83118752851.

It can be written as a sum of positive squares in 4 ways, for example, as 7505969769 + 8319811369 = 86637^2 + 91213^2 .

It is a junction number, because it is equal to n+sod(n) for n = 15825781091 and 15825781100.

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, 97456 + ... + 202852.

Almost surely, 2^15825781138 is an apocalyptic number.

15825781138 is a deficient number, since it is larger than the sum of its proper divisors (8097456902).

15825781138 is a wasteful number, since it uses less digits than its factorization.

15825781138 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 105981.

The product of its digits is 537600, while the sum is 49.

The spelling of 15825781138 in words is "fifteen billion, eight hundred twenty-five million, seven hundred eighty-one thousand, one hundred thirty-eight".