138870531 has 20 divisors (see below), whose sum is σ = 214605600. Its totient is φ = 89386416.

The previous prime is 138870517. The next prime is 138870539. The reversal of 138870531 is 135078831.

138870531 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 138870531 - 2⁵ = 138870499 is a prime.

It is a super-2 number, since 2×138870531² = 38570048760443922, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (138870539) 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, 27211 + ... + 31908.

It is an arithmetic number, because the mean of its divisors is an integer number (10730280).

Almost surely, 2^138870531 is an apocalyptic number.

138870531 is a deficient number, since it is larger than the sum of its proper divisors (75735069).

138870531 is an equidigital number, since it uses as much as digits as its factorization.

138870531 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 59160 (or 59151 counting only the distinct ones).

The product of its (nonzero) digits is 20160, while the sum is 36.

The square root of 138870531 is about 11784.3341347740. The cubic root of 138870531 is about 517.8492664286.

The spelling of 138870531 in words is "one hundred thirty-eight million, eight hundred seventy thousand, five hundred thirty-one".