138890431 has 4 divisors (see below), whose sum is σ = 138915000. Its totient is φ = 138865864.

The previous prime is 138890429. The next prime is 138890441. The reversal of 138890431 is 134098831.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 134098831 = 4049 ⋅33119.

It is a cyclic number.

It is not a de Polignac number, because 138890431 - 2¹ = 138890429 is a prime.

It is a super-2 number, since 2×138890431² = 38581103646731522, 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 (138890441) 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, 945 + ... + 16693.

It is an arithmetic number, because the mean of its divisors is an integer number (34728750).

Almost surely, 2^138890431 is an apocalyptic number.

138890431 is a deficient number, since it is larger than the sum of its proper divisors (24569).

138890431 is an equidigital number, since it uses as much as digits as its factorization.

138890431 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 24568.

The product of its (nonzero) digits is 20736, while the sum is 37.

The square root of 138890431 is about 11785.1784458276. The cubic root of 138890431 is about 517.8740009977.

It can be divided in two parts, 1388 and 90431, that added together give a palindrome (91819).

The spelling of 138890431 in words is "one hundred thirty-eight million, eight hundred ninety thousand, four hundred thirty-one".