138426979681 has 2 divisors, whose sum is σ = 138426979682. Its totient is φ = 138426979680.

The previous prime is 138426979667. The next prime is 138426979703. The reversal of 138426979681 is 186979624831.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 108570250000 + 29856729681 = 329500^2 + 172791^2 .

It is a cyclic number.

It is not a de Polignac number, because 138426979681 - 2⁹ = 138426979169 is a prime.

It is a super-2 number, since 2×138426979681² (a number of 23 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (138426979651) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 69213489840 + 69213489841.

It is an arithmetic number, because the mean of its divisors is an integer number (69213489841).

Almost surely, 2^138426979681 is an apocalyptic number.

It is an amenable number.

138426979681 is a deficient number, since it is larger than the sum of its proper divisors (1).

138426979681 is an equidigital number, since it uses as much as digits as its factorization.

138426979681 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 31352832, while the sum is 64.

The spelling of 138426979681 in words is "one hundred thirty-eight billion, four hundred twenty-six million, nine hundred seventy-nine thousand, six hundred eighty-one".