251255491 has 2 divisors, whose sum is σ = 251255492. Its totient is φ = 251255490.

The previous prime is 251255447. The next prime is 251255497. The reversal of 251255491 is 194552152.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 251255491 - 2⁹ = 251254979 is a prime.

It is not a weakly prime, because it can be changed into another prime (251255497) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 125627745 + 125627746.

It is an arithmetic number, because the mean of its divisors is an integer number (125627746).

Almost surely, 2^251255491 is an apocalyptic number.

251255491 is a deficient number, since it is larger than the sum of its proper divisors (1).

251255491 is an equidigital number, since it uses as much as digits as its factorization.

251255491 is an evil number, because the sum of its binary digits is even.

The product of its digits is 18000, while the sum is 34.

The square root of 251255491 is about 15851.0406913868. The cubic root of 251255491 is about 631.0133109174.

The spelling of 251255491 in words is "two hundred fifty-one million, two hundred fifty-five thousand, four hundred ninety-one".