138115961 has 2 divisors, whose sum is σ = 138115962. Its totient is φ = 138115960.

The previous prime is 138115909. The next prime is 138115979. The reversal of 138115961 is 169511831.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 125865961 + 12250000 = 11219^2 + 3500^2 .

It is an emirp because it is prime and its reverse (169511831) is a distict prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-138115961 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (138115981) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 69057980 + 69057981.

It is an arithmetic number, because the mean of its divisors is an integer number (69057981).

Almost surely, 2^138115961 is an apocalyptic number.

It is an amenable number.

138115961 is a deficient number, since it is larger than the sum of its proper divisors (1).

138115961 is an equidigital number, since it uses as much as digits as its factorization.

138115961 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 6480, while the sum is 35.

The square root of 138115961 is about 11752.2747159858. The cubic root of 138115961 is about 516.9096300685.

The spelling of 138115961 in words is "one hundred thirty-eight million, one hundred fifteen thousand, nine hundred sixty-one".