257438729 has 2 divisors, whose sum is σ = 257438730. Its totient is φ = 257438728.

The previous prime is 257438659. The next prime is 257438737. The reversal of 257438729 is 927834752.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 250272400 + 7166329 = 15820^2 + 2677^2 .

It is a cyclic number.

It is not a de Polignac number, because 257438729 - 2⁸ = 257438473 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (257438789) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 128719364 + 128719365.

It is an arithmetic number, because the mean of its divisors is an integer number (128719365).

Almost surely, 2^257438729 is an apocalyptic number.

It is an amenable number.

257438729 is a deficient number, since it is larger than the sum of its proper divisors (1).

257438729 is an equidigital number, since it uses as much as digits as its factorization.

257438729 is an evil number, because the sum of its binary digits is even.

The product of its digits is 846720, while the sum is 47.

The square root of 257438729 is about 16044.8972885463. The cubic root of 257438729 is about 636.1476993374.

The spelling of 257438729 in words is "two hundred fifty-seven million, four hundred thirty-eight thousand, seven hundred twenty-nine".