138978911 has 2 divisors, whose sum is σ = 138978912. Its totient is φ = 138978910.

The previous prime is 138978907. The next prime is 138978937. The reversal of 138978911 is 119879831.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 138978911 - 2² = 138978907 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (138978941) 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 as a sum of consecutive naturals, namely, 69489455 + 69489456.

It is an arithmetic number, because the mean of its divisors is an integer number (69489456).

Almost surely, 2^138978911 is an apocalyptic number.

138978911 is a deficient number, since it is larger than the sum of its proper divisors (1).

138978911 is an equidigital number, since it uses as much as digits as its factorization.

138978911 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 108864, while the sum is 47.

The square root of 138978911 is about 11788.9317158087. The cubic root of 138978911 is about 517.9839480126.

The spelling of 138978911 in words is "one hundred thirty-eight million, nine hundred seventy-eight thousand, nine hundred eleven".