251278022761 has 2 divisors, whose sum is σ = 251278022762. Its totient is φ = 251278022760.

The previous prime is 251278022717. The next prime is 251278022797. The reversal of 251278022761 is 167220872152.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 174928043536 + 76349979225 = 418244^2 + 276315^2 .

It is a cyclic number.

It is not a de Polignac number, because 251278022761 - 2¹⁵ = 251277989993 is a prime.

It is not a weakly prime, because it can be changed into another prime (251278020761) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 125639011380 + 125639011381.

It is an arithmetic number, because the mean of its divisors is an integer number (125639011381).

Almost surely, 2^251278022761 is an apocalyptic number.

It is an amenable number.

251278022761 is a deficient number, since it is larger than the sum of its proper divisors (1).

251278022761 is an equidigital number, since it uses as much as digits as its factorization.

251278022761 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 188160, while the sum is 43.

The spelling of 251278022761 in words is "two hundred fifty-one billion, two hundred seventy-eight million, twenty-two thousand, seven hundred sixty-one".