139408657 has 2 divisors, whose sum is σ = 139408658. Its totient is φ = 139408656.

The previous prime is 139408631. The next prime is 139408669. The reversal of 139408657 is 756804931.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 96059601 + 43349056 = 9801^2 + 6584^2 .

It is a cyclic number.

It is not a de Polignac number, because 139408657 - 2²³ = 131020049 is a prime.

It is equal to p_7880587 and since 139408657 and 7880587 have the same sum of digits, it is a Honaker prime.

It is not a weakly prime, because it can be changed into another prime (139408697) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 69704328 + 69704329.

It is an arithmetic number, because the mean of its divisors is an integer number (69704329).

Almost surely, 2^139408657 is an apocalyptic number.

It is an amenable number.

139408657 is a deficient number, since it is larger than the sum of its proper divisors (1).

139408657 is an equidigital number, since it uses as much as digits as its factorization.

139408657 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 181440, while the sum is 43.

The square root of 139408657 is about 11807.1443202834. The cubic root of 139408657 is about 518.5172962765.

The spelling of 139408657 in words is "one hundred thirty-nine million, four hundred eight thousand, six hundred fifty-seven".