257507561 has 4 divisors (see below), whose sum is σ = 257732052. Its totient is φ = 257283072.

The previous prime is 257507543. The next prime is 257507567. The reversal of 257507561 is 165705752.

257507561 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 206813161 + 50694400 = 14381^2 + 7120^2 .

It is a cyclic number.

It is not a de Polignac number, because 257507561 - 2¹⁰ = 257506537 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (257507567) 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, 110516 + ... + 112821.

It is an arithmetic number, because the mean of its divisors is an integer number (64433013).

Almost surely, 2^257507561 is an apocalyptic number.

It is an amenable number.

257507561 is a deficient number, since it is larger than the sum of its proper divisors (224491).

257507561 is a wasteful number, since it uses less digits than its factorization.

257507561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 224490.

The product of its (nonzero) digits is 73500, while the sum is 38.

The square root of 257507561 is about 16047.0421261988. The cubic root of 257507561 is about 636.2043903886.

The spelling of 257507561 in words is "two hundred fifty-seven million, five hundred seven thousand, five hundred sixty-one".