257139979 has 2 divisors, whose sum is σ = 257139980. Its totient is φ = 257139978.

The previous prime is 257139929. The next prime is 257139989. The reversal of 257139979 is 979931752.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 257139979 - 2⁷ = 257139851 is a prime.

It is a super-2 number, since 2×257139979² = 132241937600240882, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (257139929) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 128569989 + 128569990.

It is an arithmetic number, because the mean of its divisors is an integer number (128569990).

Almost surely, 2^257139979 is an apocalyptic number.

257139979 is a deficient number, since it is larger than the sum of its proper divisors (1).

257139979 is an equidigital number, since it uses as much as digits as its factorization.

257139979 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1071630, while the sum is 52.

The square root of 257139979 is about 16035.5847726237. The cubic root of 257139979 is about 635.9015272498.

The spelling of 257139979 in words is "two hundred fifty-seven million, one hundred thirty-nine thousand, nine hundred seventy-nine".