138549857 has 2 divisors, whose sum is σ = 138549858. Its totient is φ = 138549856.

The previous prime is 138549833. The next prime is 138549959. The reversal of 138549857 is 758945831.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 135466321 + 3083536 = 11639^2 + 1756^2 .

It is a cyclic number.

It is not a de Polignac number, because 138549857 - 2⁸ = 138549601 is a prime.

It is not a weakly prime, because it can be changed into another prime (138549157) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 69274928 + 69274929.

It is an arithmetic number, because the mean of its divisors is an integer number (69274929).

Almost surely, 2^138549857 is an apocalyptic number.

It is an amenable number.

138549857 is a deficient number, since it is larger than the sum of its proper divisors (1).

138549857 is an equidigital number, since it uses as much as digits as its factorization.

138549857 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1209600, while the sum is 50.

The square root of 138549857 is about 11770.7203263012. The cubic root of 138549857 is about 517.4503606303.

The spelling of 138549857 in words is "one hundred thirty-eight million, five hundred forty-nine thousand, eight hundred fifty-seven".