138431 has 6 divisors (see below), whose sum is σ = 147360. Its totient is φ = 130016.

The previous prime is 138427. The next prime is 138433. The reversal of 138431 is 134831.

It is a happy number.

It is not a de Polignac number, because 138431 - 2² = 138427 is a prime.

It is a super-2 number, since 2×138431² = 38326283522, 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 (138433) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 50 + ... + 528.

It is an arithmetic number, because the mean of its divisors is an integer number (24560).

2¹³⁸⁴³¹ is an apocalyptic number.

138431 is a deficient number, since it is larger than the sum of its proper divisors (8929).

138431 is an equidigital number, since it uses as much as digits as its factorization.

138431 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 513 (or 496 counting only the distinct ones).

The product of its digits is 288, while the sum is 20.

The square root of 138431 is about 372.0631666801. The cubic root of 138431 is about 51.7302350871.

Subtracting from 138431 its reverse (134831), we obtain a square (3600 = 60²).

The spelling of 138431 in words is "one hundred thirty-eight thousand, four hundred thirty-one".