138417931 has 4 divisors (see below), whose sum is σ = 138441600. Its totient is φ = 138394264.

The previous prime is 138417919. The next prime is 138417941. The reversal of 138417931 is 139714831.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length, and also an emirpimes, since its reverse is a distinct semiprime: 139714831 = 709 ⋅197059.

It is a cyclic number.

It is not a de Polignac number, because 138417931 - 2¹¹ = 138415883 is a prime.

It is a super-2 number, since 2×138417931² = 38319047244641522, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (138417941) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4005 + ... + 17113.

It is an arithmetic number, because the mean of its divisors is an integer number (34610400).

Almost surely, 2^138417931 is an apocalyptic number.

138417931 is a deficient number, since it is larger than the sum of its proper divisors (23669).

138417931 is a wasteful number, since it uses less digits than its factorization.

138417931 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 23668.

The product of its digits is 18144, while the sum is 37.

The square root of 138417931 is about 11765.1150015629. The cubic root of 138417931 is about 517.2860711911.

The spelling of 138417931 in words is "one hundred thirty-eight million, four hundred seventeen thousand, nine hundred thirty-one".