138235831 has 4 divisors (see below), whose sum is σ = 139116472. Its totient is φ = 137355192.

The previous prime is 138235829. The next prime is 138235847. The reversal of 138235831 is 138532831.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 138235831 - 2¹ = 138235829 is a prime.

It is a super-2 number, since 2×138235831² = 38218289944521122, 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 (138235631) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 440085 + ... + 440398.

It is an arithmetic number, because the mean of its divisors is an integer number (34779118).

Almost surely, 2^138235831 is an apocalyptic number.

138235831 is a deficient number, since it is larger than the sum of its proper divisors (880641).

138235831 is an equidigital number, since it uses as much as digits as its factorization.

138235831 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 880640.

The product of its digits is 17280, while the sum is 34.

The square root of 138235831 is about 11757.3734736973. The cubic root of 138235831 is about 517.0591277324.

The spelling of 138235831 in words is "one hundred thirty-eight million, two hundred thirty-five thousand, eight hundred thirty-one".