138940791 has 24 divisors (see below), whose sum is σ = 210212352. Its totient is φ = 81483600.

The previous prime is 138940771. The next prime is 138940807. The reversal of 138940791 is 197049831.

It is a happy number.

It is not a de Polignac number, because 138940791 - 2¹⁵ = 138908023 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (138940721) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 5080 + ... + 17426.

It is an arithmetic number, because the mean of its divisors is an integer number (8758848).

Almost surely, 2^138940791 is an apocalyptic number.

138940791 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

138940791 is a deficient number, since it is larger than the sum of its proper divisors (71271561).

138940791 is a wasteful number, since it uses less digits than its factorization.

138940791 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12403 (or 12392 counting only the distinct ones).

The product of its (nonzero) digits is 54432, while the sum is 42.

The square root of 138940791 is about 11787.3148341766. The cubic root of 138940791 is about 517.9365850625.

The spelling of 138940791 in words is "one hundred thirty-eight million, nine hundred forty thousand, seven hundred ninety-one".