251553161 has 2 divisors, whose sum is σ = 251553162. Its totient is φ = 251553160.

The previous prime is 251553157. The next prime is 251553187. The reversal of 251553161 is 161355152.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 196140025 + 55413136 = 14005^2 + 7444^2 .

It is a cyclic number.

It is not a de Polignac number, because 251553161 - 2² = 251553157 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 (251553101) 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, 125776580 + 125776581.

It is an arithmetic number, because the mean of its divisors is an integer number (125776581).

Almost surely, 2^251553161 is an apocalyptic number.

It is an amenable number.

251553161 is a deficient number, since it is larger than the sum of its proper divisors (1).

251553161 is an equidigital number, since it uses as much as digits as its factorization.

251553161 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 4500, while the sum is 29.

The square root of 251553161 is about 15860.4275163061. The cubic root of 251553161 is about 631.2624061085.

The spelling of 251553161 in words is "two hundred fifty-one million, five hundred fifty-three thousand, one hundred sixty-one".