251261520193 has 2 divisors, whose sum is σ = 251261520194. Its totient is φ = 251261520192.

The previous prime is 251261520071. The next prime is 251261520239. The reversal of 251261520193 is 391025162152.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 158290192449 + 92971327744 = 397857^2 + 304912^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-251261520193 is a prime.

It is not a weakly prime, because it can be changed into another prime (251261520893) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 125630760096 + 125630760097.

It is an arithmetic number, because the mean of its divisors is an integer number (125630760097).

Almost surely, 2^251261520193 is an apocalyptic number.

It is an amenable number.

251261520193 is a deficient number, since it is larger than the sum of its proper divisors (1).

251261520193 is an equidigital number, since it uses as much as digits as its factorization.

251261520193 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 32400, while the sum is 37.

The spelling of 251261520193 in words is "two hundred fifty-one billion, two hundred sixty-one million, five hundred twenty thousand, one hundred ninety-three".