257345765 has 8 divisors (see below), whose sum is σ = 310782840. Its totient is φ = 204564672.

The previous prime is 257345761. The next prime is 257345789. The reversal of 257345765 is 567543752.

It is a Cunningham number, because it is equal to 16042²+1.

It can be written as a sum of positive squares in 4 ways, for example, as 1 + 257345764 = 1^2 + 16042^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 257345765 - 2² = 257345761 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (257345761) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 163130 + ... + 164699.

It is an arithmetic number, because the mean of its divisors is an integer number (38847855).

Almost surely, 2^257345765 is an apocalyptic number.

It is an amenable number.

257345765 is a deficient number, since it is larger than the sum of its proper divisors (53437075).

257345765 is a wasteful number, since it uses less digits than its factorization.

257345765 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 327991.

The product of its digits is 882000, while the sum is 44.

The square root of 257345765 is about 16042.0000311682. Note that the first 4 decimals coincide. The cubic root of 257345765 is about 636.0711167723.

The spelling of 257345765 in words is "two hundred fifty-seven million, three hundred forty-five thousand, seven hundred sixty-five".