257261729 has 4 divisors (see below), whose sum is σ = 270801840. Its totient is φ = 243721620.

The previous prime is 257261723. The next prime is 257261749. The reversal of 257261729 is 927162752.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 257261729 - 2²⁴ = 240484513 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (257261723) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 6770027 + ... + 6770064.

It is an arithmetic number, because the mean of its divisors is an integer number (67700460).

Almost surely, 2^257261729 is an apocalyptic number.

It is an amenable number.

257261729 is a deficient number, since it is larger than the sum of its proper divisors (13540111).

257261729 is a wasteful number, since it uses less digits than its factorization.

257261729 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13540110.

The product of its digits is 105840, while the sum is 41.

The square root of 257261729 is about 16039.3805678399. The cubic root of 257261729 is about 636.0018731074.

The spelling of 257261729 in words is "two hundred fifty-seven million, two hundred sixty-one thousand, seven hundred twenty-nine".