139431537 has 20 divisors (see below), whose sum is σ = 238042816. Its totient is φ = 79674840.

The previous prime is 139431527. The next prime is 139431541. The reversal of 139431537 is 735134931.

139431537 is a `hidden beast` number, since 1 + 3 + 94 + 31 + 537 = 666.

139431537 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 139431537 - 2¹⁰ = 139430513 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (139431527) by changing a digit.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 122389 + ... + 123522.

Almost surely, 2^139431537 is an apocalyptic number.

It is an amenable number.

139431537 is a deficient number, since it is larger than the sum of its proper divisors (98611279).

139431537 is an equidigital number, since it uses as much as digits as its factorization.

139431537 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 245930 (or 245921 counting only the distinct ones).

The product of its digits is 34020, while the sum is 36.

The square root of 139431537 is about 11808.1131854331. The cubic root of 139431537 is about 518.5456613891.

The spelling of 139431537 in words is "one hundred thirty-nine million, four hundred thirty-one thousand, five hundred thirty-seven".