138986431 has 4 divisors (see below), whose sum is σ = 139425192. Its totient is φ = 138547672.

The previous prime is 138986417. The next prime is 138986437. The reversal of 138986431 is 134689831.

138986431 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 134689831 = 2069 ⋅65099.

It is a cyclic number.

It is not a de Polignac number, because 138986431 - 2⁵ = 138986399 is a prime.

It is a super-2 number, since 2×138986431² = 38634456004235522, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (138986437) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 218905 + ... + 219538.

It is an arithmetic number, because the mean of its divisors is an integer number (34856298).

Almost surely, 2^138986431 is an apocalyptic number.

138986431 is a deficient number, since it is larger than the sum of its proper divisors (438761).

138986431 is an equidigital number, since it uses as much as digits as its factorization.

138986431 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 438760.

The product of its digits is 124416, while the sum is 43.

The square root of 138986431 is about 11789.2506547278. The cubic root of 138986431 is about 517.9932903629.

The spelling of 138986431 in words is "one hundred thirty-eight million, nine hundred eighty-six thousand, four hundred thirty-one".