257981 has 2 divisors, whose sum is σ = 257982. Its totient is φ = 257980.

The previous prime is 257953. The next prime is 257987. The reversal of 257981 is 189752.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 241081 + 16900 = 491^2 + 130^2 .

It is a cyclic number.

It is not a de Polignac number, because 257981 - 2¹⁰ = 256957 is a prime.

It is a super-2 number, since 2×257981² = 133108392722, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (257987) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 128990 + 128991.

It is an arithmetic number, because the mean of its divisors is an integer number (128991).

2²⁵⁷⁹⁸¹ is an apocalyptic number.

It is an amenable number.

257981 is a deficient number, since it is larger than the sum of its proper divisors (1).

257981 is an equidigital number, since it uses as much as digits as its factorization.

257981 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 5040, while the sum is 32.

The square root of 257981 is about 507.9183005169. The cubic root of 257981 is about 63.6594048289.

The spelling of 257981 in words is "two hundred fifty-seven thousand, nine hundred eighty-one".