138255961 has 2 divisors, whose sum is σ = 138255962. Its totient is φ = 138255960.

The previous prime is 138255947. The next prime is 138255991. The reversal of 138255961 is 169552831.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 135582736 + 2673225 = 11644^2 + 1635^2 .

It is a cyclic number.

It is not a de Polignac number, because 138255961 - 2²⁵ = 104701529 is a prime.

It is a super-2 number, since 2×138255961² = 38229421504067042, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (138255991) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 69127980 + 69127981.

It is an arithmetic number, because the mean of its divisors is an integer number (69127981).

Almost surely, 2^138255961 is an apocalyptic number.

It is an amenable number.

138255961 is a deficient number, since it is larger than the sum of its proper divisors (1).

138255961 is an equidigital number, since it uses as much as digits as its factorization.

138255961 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 64800, while the sum is 40.

The square root of 138255961 is about 11758.2295010771. The cubic root of 138255961 is about 517.0842246868.

The spelling of 138255961 in words is "one hundred thirty-eight million, two hundred fifty-five thousand, nine hundred sixty-one".