138481731 has 20 divisors (see below), whose sum is σ = 207296232. Its totient is φ = 92130048.

The previous prime is 138481727. The next prime is 138481753. The reversal of 138481731 is 137184831.

It is not a de Polignac number, because 138481731 - 2² = 138481727 is a prime.

It is a super-2 number, since 2×138481731² = 38354379641512722, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (138481771) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 45256 + ... + 48218.

Almost surely, 2^138481731 is an apocalyptic number.

138481731 is a deficient number, since it is larger than the sum of its proper divisors (68814501).

138481731 is an equidigital number, since it uses as much as digits as its factorization.

138481731 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3552 (or 3543 counting only the distinct ones).

The product of its digits is 16128, while the sum is 36.

The square root of 138481731 is about 11767.8260949081. The cubic root of 138481731 is about 517.3655353227.

The spelling of 138481731 in words is "one hundred thirty-eight million, four hundred eighty-one thousand, seven hundred thirty-one".