251121697 has 2 divisors, whose sum is σ = 251121698. Its totient is φ = 251121696.

The previous prime is 251121649. The next prime is 251121713. The reversal of 251121697 is 796121152.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 223831521 + 27290176 = 14961^2 + 5224^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-251121697 is a prime.

It is not a weakly prime, because it can be changed into another prime (251121097) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 125560848 + 125560849.

It is an arithmetic number, because the mean of its divisors is an integer number (125560849).

Almost surely, 2^251121697 is an apocalyptic number.

It is an amenable number.

251121697 is a deficient number, since it is larger than the sum of its proper divisors (1).

251121697 is an equidigital number, since it uses as much as digits as its factorization.

251121697 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 7560, while the sum is 34.

The square root of 251121697 is about 15846.8197755890. The cubic root of 251121697 is about 630.9012857903.

The spelling of 251121697 in words is "two hundred fifty-one million, one hundred twenty-one thousand, six hundred ninety-seven".