257017861 has 2 divisors, whose sum is σ = 257017862. Its totient is φ = 257017860.

The previous prime is 257017819. The next prime is 257017877. The reversal of 257017861 is 168710752.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 205033761 + 51984100 = 14319^2 + 7210^2 .

It is a cyclic number.

It is not a de Polignac number, because 257017861 - 2⁹ = 257017349 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 257017861.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (257017361) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 128508930 + 128508931.

It is an arithmetic number, because the mean of its divisors is an integer number (128508931).

Almost surely, 2^257017861 is an apocalyptic number.

It is an amenable number.

257017861 is a deficient number, since it is larger than the sum of its proper divisors (1).

257017861 is an equidigital number, since it uses as much as digits as its factorization.

257017861 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 23520, while the sum is 37.

The square root of 257017861 is about 16031.7766014874. The cubic root of 257017861 is about 635.8008462650.

The spelling of 257017861 in words is "two hundred fifty-seven million, seventeen thousand, eight hundred sixty-one".