251195491 has 2 divisors, whose sum is σ = 251195492. Its totient is φ = 251195490.

The previous prime is 251195467. The next prime is 251195507. The reversal of 251195491 is 194591152.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 251195491 - 2⁷ = 251195363 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 251195491.

It is not a weakly prime, because it can be changed into another prime (251195411) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 125597745 + 125597746.

It is an arithmetic number, because the mean of its divisors is an integer number (125597746).

Almost surely, 2^251195491 is an apocalyptic number.

251195491 is a deficient number, since it is larger than the sum of its proper divisors (1).

251195491 is an equidigital number, since it uses as much as digits as its factorization.

251195491 is an evil number, because the sum of its binary digits is even.

The product of its digits is 16200, while the sum is 37.

The square root of 251195491 is about 15849.1479581711. The cubic root of 251195491 is about 630.9630781011.

The spelling of 251195491 in words is "two hundred fifty-one million, one hundred ninety-five thousand, four hundred ninety-one".