138275991 has 70 divisors (see below), whose sum is σ = 244919440. Its totient is φ = 78014664.

The previous prime is 138275989. The next prime is 138276001. The reversal of 138275991 is 199572831.

138275991 is a `hidden beast` number, since 1 + 38 + 27 + 599 + 1 = 666.

It is not a de Polignac number, because 138275991 - 2¹ = 138275989 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (138275971) by changing a digit.

It is a polite number, since it can be written in 69 ways as a sum of consecutive naturals, for example, 1750290 + ... + 1750368.

Almost surely, 2^138275991 is an apocalyptic number.

138275991 is a deficient number, since it is larger than the sum of its proper divisors (106643449).

138275991 is an frugal number, since it uses more digits than its factorization.

138275991 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 125 (or 89 counting only the distinct ones).

The product of its digits is 136080, while the sum is 45.

The square root of 138275991 is about 11759.0812141085. The cubic root of 138275991 is about 517.1091945490.

The spelling of 138275991 in words is "one hundred thirty-eight million, two hundred seventy-five thousand, nine hundred ninety-one".