687192138 has 12 divisors (see below), whose sum is σ = 1488916338. Its totient is φ = 229064040.

The previous prime is 687192119. The next prime is 687192161. The reversal of 687192138 is 831291786.

687192138 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in only one way, i.e., 378030249 + 309161889 = 19443^2 + 17583^2 .

It is a super-2 number, since 2×687192138² = 944466069058022088, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 687192093 and 687192102.

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 19088653 + ... + 19088688.

Almost surely, 2^687192138 is an apocalyptic number.

687192138 is an abundant number, since it is smaller than the sum of its proper divisors (801724200).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

687192138 is a wasteful number, since it uses less digits than its factorization.

687192138 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 38177349 (or 38177346 counting only the distinct ones).

The product of its digits is 145152, while the sum is 45.

The square root of 687192138 is about 26214.3498488900. The cubic root of 687192138 is about 882.4553235441.

The spelling of 687192138 in words is "six hundred eighty-seven million, one hundred ninety-two thousand, one hundred thirty-eight".