138175561 has 2 divisors, whose sum is σ = 138175562. Its totient is φ = 138175560.

The previous prime is 138175511. The next prime is 138175567. The reversal of 138175561 is 165571831.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 115670025 + 22505536 = 10755^2 + 4744^2 .

It is an emirp because it is prime and its reverse (165571831) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 138175561 - 2¹¹ = 138173513 is a prime.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 138175561.

It is not a weakly prime, because it can be changed into another prime (138175567) 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 as a sum of consecutive naturals, namely, 69087780 + 69087781.

It is an arithmetic number, because the mean of its divisors is an integer number (69087781).

Almost surely, 2^138175561 is an apocalyptic number.

It is an amenable number.

138175561 is a deficient number, since it is larger than the sum of its proper divisors (1).

138175561 is an equidigital number, since it uses as much as digits as its factorization.

138175561 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 25200, while the sum is 37.

The square root of 138175561 is about 11754.8101218182. The cubic root of 138175561 is about 516.9839719075.

The spelling of 138175561 in words is "one hundred thirty-eight million, one hundred seventy-five thousand, five hundred sixty-one".