257659810981 has 2 divisors, whose sum is σ = 257659810982. Its totient is φ = 257659810980.

The previous prime is 257659810979. The next prime is 257659811011. The reversal of 257659810981 is 189018956752.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 255665741956 + 1994069025 = 505634^2 + 44655^2 .

It is a cyclic number.

It is not a de Polignac number, because 257659810981 - 2¹ = 257659810979 is a prime.

It is a super-2 number, since 2×257659810981² (a number of 24 digits) contains 22 as substring.

Together with 257659810979, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (257659810921) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 128829905490 + 128829905491.

It is an arithmetic number, because the mean of its divisors is an integer number (128829905491).

Almost surely, 2^257659810981 is an apocalyptic number.

It is an amenable number.

257659810981 is a deficient number, since it is larger than the sum of its proper divisors (1).

257659810981 is an equidigital number, since it uses as much as digits as its factorization.

257659810981 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 10886400, while the sum is 61.

The spelling of 257659810981 in words is "two hundred fifty-seven billion, six hundred fifty-nine million, eight hundred ten thousand, nine hundred eighty-one".