251261339977 has 2 divisors, whose sum is σ = 251261339978. Its totient is φ = 251261339976.

The previous prime is 251261339963. The next prime is 251261339981. The reversal of 251261339977 is 779933162152.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 242631115776 + 8630224201 = 492576^2 + 92899^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-251261339977 is a prime.

It is not a weakly prime, because it can be changed into another prime (251261339177) 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, 125630669988 + 125630669989.

It is an arithmetic number, because the mean of its divisors is an integer number (125630669989).

Almost surely, 2^251261339977 is an apocalyptic number.

It is an amenable number.

251261339977 is a deficient number, since it is larger than the sum of its proper divisors (1).

251261339977 is an equidigital number, since it uses as much as digits as its factorization.

251261339977 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 4286520, while the sum is 55.

The spelling of 251261339977 in words is "two hundred fifty-one billion, two hundred sixty-one million, three hundred thirty-nine thousand, nine hundred seventy-seven".