257129891 has 2 divisors, whose sum is σ = 257129892. Its totient is φ = 257129890.

The previous prime is 257129843. The next prime is 257129923. The reversal of 257129891 is 198921752.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-257129891 is a prime.

It is a super-2 number, since 2×257129891² = 132231561691343762, which contains 22 as substring.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (257129591) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 128564945 + 128564946.

It is an arithmetic number, because the mean of its divisors is an integer number (128564946).

Almost surely, 2^257129891 is an apocalyptic number.

257129891 is a deficient number, since it is larger than the sum of its proper divisors (1).

257129891 is an equidigital number, since it uses as much as digits as its factorization.

257129891 is an evil number, because the sum of its binary digits is even.

The product of its digits is 90720, while the sum is 44.

The square root of 257129891 is about 16035.2702191139. The cubic root of 257129891 is about 635.8932113401.

The spelling of 257129891 in words is "two hundred fifty-seven million, one hundred twenty-nine thousand, eight hundred ninety-one".