257117971961 has 2 divisors, whose sum is σ = 257117971962. Its totient is φ = 257117971960.

The previous prime is 257117971907. The next prime is 257117971963. The reversal of 257117971961 is 169179711752.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 256643560000 + 474411961 = 506600^2 + 21781^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-257117971961 is a prime.

It is a super-2 number, since 2×257117971961² (a number of 24 digits) contains 22 as substring.

Together with 257117971963, it forms a pair of twin primes.

It is a Chen prime.

It is a junction number, because it is equal to n+sod(n) for n = 257117971897 and 257117971906.

It is not a weakly prime, because it can be changed into another prime (257117971963) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 128558985980 + 128558985981.

It is an arithmetic number, because the mean of its divisors is an integer number (128558985981).

Almost surely, 2^257117971961 is an apocalyptic number.

It is an amenable number.

257117971961 is a deficient number, since it is larger than the sum of its proper divisors (1).

257117971961 is an equidigital number, since it uses as much as digits as its factorization.

257117971961 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1666980, while the sum is 56.

The spelling of 257117971961 in words is "two hundred fifty-seven billion, one hundred seventeen million, nine hundred seventy-one thousand, nine hundred sixty-one".