138918331 has 2 divisors, whose sum is σ = 138918332. Its totient is φ = 138918330.

The previous prime is 138918319. The next prime is 138918341. The reversal of 138918331 is 133819831.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 138918331 - 2¹³ = 138910139 is a prime.

It is a super-2 number, since 2×138918331² = 38596605375651122, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (138918341) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 69459165 + 69459166.

It is an arithmetic number, because the mean of its divisors is an integer number (69459166).

Almost surely, 2^138918331 is an apocalyptic number.

138918331 is a deficient number, since it is larger than the sum of its proper divisors (1).

138918331 is an equidigital number, since it uses as much as digits as its factorization.

138918331 is an evil number, because the sum of its binary digits is even.

The product of its digits is 15552, while the sum is 37.

The square root of 138918331 is about 11786.3620765697. The cubic root of 138918331 is about 517.9086751341.

It can be divided in two parts, 13891 and 8331, that added together give a palindrome (22222).

The spelling of 138918331 in words is "one hundred thirty-eight million, nine hundred eighteen thousand, three hundred thirty-one".