138711931 has 4 divisors (see below), whose sum is σ = 138735864. Its totient is φ = 138688000.

The previous prime is 138711917. The next prime is 138711943. The reversal of 138711931 is 139117831.

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 138711931 - 2⁷ = 138711803 is a prime.

It is a super-2 number, since 2×138711931² = 38481999603497522, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (138711961) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2811 + ... + 16891.

It is an arithmetic number, because the mean of its divisors is an integer number (34683966).

Almost surely, 2^138711931 is an apocalyptic number.

138711931 is a deficient number, since it is larger than the sum of its proper divisors (23933).

138711931 is an equidigital number, since it uses as much as digits as its factorization.

138711931 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 23932.

The product of its digits is 4536, while the sum is 34.

The square root of 138711931 is about 11777.6029394780. The cubic root of 138711931 is about 517.6520511295.

The spelling of 138711931 in words is "one hundred thirty-eight million, seven hundred eleven thousand, nine hundred thirty-one".