138731557 has 2 divisors, whose sum is σ = 138731558. Its totient is φ = 138731556.

The previous prime is 138731533. The next prime is 138731617. The reversal of 138731557 is 755137831.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 115218756 + 23512801 = 10734^2 + 4849^2 .

It is a cyclic number.

It is not a de Polignac number, because 138731557 - 2¹⁵ = 138698789 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (138731057) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 69365778 + 69365779.

It is an arithmetic number, because the mean of its divisors is an integer number (69365779).

Almost surely, 2^138731557 is an apocalyptic number.

It is an amenable number.

138731557 is a deficient number, since it is larger than the sum of its proper divisors (1).

138731557 is an equidigital number, since it uses as much as digits as its factorization.

138731557 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 88200, while the sum is 40.

The square root of 138731557 is about 11778.4361016223. The cubic root of 138731557 is about 517.6764637376.

The spelling of 138731557 in words is "one hundred thirty-eight million, seven hundred thirty-one thousand, five hundred fifty-seven".