251967161 has 2 divisors, whose sum is σ = 251967162. Its totient is φ = 251967160.

The previous prime is 251967119. The next prime is 251967173. The reversal of 251967161 is 161769152.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 220819600 + 31147561 = 14860^2 + 5581^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-251967161 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (251960161) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 125983580 + 125983581.

It is an arithmetic number, because the mean of its divisors is an integer number (125983581).

Almost surely, 2^251967161 is an apocalyptic number.

It is an amenable number.

251967161 is a deficient number, since it is larger than the sum of its proper divisors (1).

251967161 is an equidigital number, since it uses as much as digits as its factorization.

251967161 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 22680, while the sum is 38.

The square root of 251967161 is about 15873.4735014111. The cubic root of 251967161 is about 631.6085216779.

The spelling of 251967161 in words is "two hundred fifty-one million, nine hundred sixty-seven thousand, one hundred sixty-one".