251536641420161 has 2 divisors, whose sum is σ = 251536641420162. Its totient is φ = 251536641420160.

The previous prime is 251536641420133. The next prime is 251536641420203. The reversal of 251536641420161 is 161024146635152.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 179059189690000 + 72477451730161 = 13381300^2 + 8513369^2 .

It is a cyclic number.

It is not a de Polignac number, because 251536641420161 - 2¹⁸ = 251536641158017 is a prime.

It is not a weakly prime, because it can be changed into another prime (251536641420661) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 125768320710080 + 125768320710081.

It is an arithmetic number, because the mean of its divisors is an integer number (125768320710081).

Almost surely, 2^{251536641420161} is an apocalyptic number.

It is an amenable number.

251536641420161 is a deficient number, since it is larger than the sum of its proper divisors (1).

251536641420161 is an equidigital number, since it uses as much as digits as its factorization.

251536641420161 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1036800, while the sum is 47.

The spelling of 251536641420161 in words is "two hundred fifty-one trillion, five hundred thirty-six billion, six hundred forty-one million, four hundred twenty thousand, one hundred sixty-one".