251361055817 has 2 divisors, whose sum is σ = 251361055818. Its totient is φ = 251361055816.

The previous prime is 251361055789. The next prime is 251361055849. The reversal of 251361055817 is 718550163152.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 248692713481 + 2668342336 = 498691^2 + 51656^2 .

It is a cyclic number.

It is not a de Polignac number, because 251361055817 - 2⁶ = 251361055753 is a prime.

It is not a weakly prime, because it can be changed into another prime (251361055877) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 125680527908 + 125680527909.

It is an arithmetic number, because the mean of its divisors is an integer number (125680527909).

Almost surely, 2^251361055817 is an apocalyptic number.

It is an amenable number.

251361055817 is a deficient number, since it is larger than the sum of its proper divisors (1).

251361055817 is an equidigital number, since it uses as much as digits as its factorization.

251361055817 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 252000, while the sum is 44.

The spelling of 251361055817 in words is "two hundred fifty-one billion, three hundred sixty-one million, fifty-five thousand, eight hundred seventeen".