251455312613 has 4 divisors (see below), whose sum is σ = 251465002188. Its totient is φ = 251445623040.

The previous prime is 251455312583. The next prime is 251455312627. The reversal of 251455312613 is 316213554152.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 122432109409 + 129023203204 = 349903^2 + 359198^2 .

It is a cyclic number.

It is not a de Polignac number, because 251455312613 - 2²⁰ = 251454264037 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (251455312513) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4805756 + ... + 4857797.

It is an arithmetic number, because the mean of its divisors is an integer number (62866250547).

Almost surely, 2^251455312613 is an apocalyptic number.

It is an amenable number.

251455312613 is a deficient number, since it is larger than the sum of its proper divisors (9689575).

251455312613 is an equidigital number, since it uses as much as digits as its factorization.

251455312613 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9689574.

The product of its digits is 108000, while the sum is 38.

Adding to 251455312613 its reverse (316213554152), we get a palindrome (567668866765).

The spelling of 251455312613 in words is "two hundred fifty-one billion, four hundred fifty-five million, three hundred twelve thousand, six hundred thirteen".