251691113 has 2 divisors, whose sum is σ = 251691114. Its totient is φ = 251691112.

The previous prime is 251691101. The next prime is 251691133. The reversal of 251691113 is 311196152.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 239878144 + 11812969 = 15488^2 + 3437^2 .

It is a cyclic number.

It is not a de Polignac number, because 251691113 - 2²⁰ = 250642537 is a prime.

It is not a weakly prime, because it can be changed into another prime (251691133) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 125845556 + 125845557.

It is an arithmetic number, because the mean of its divisors is an integer number (125845557).

Almost surely, 2^251691113 is an apocalyptic number.

It is an amenable number.

251691113 is a deficient number, since it is larger than the sum of its proper divisors (1).

251691113 is an equidigital number, since it uses as much as digits as its factorization.

251691113 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1620, while the sum is 29.

The square root of 251691113 is about 15864.7758572253. The cubic root of 251691113 is about 631.3777799947.

The spelling of 251691113 in words is "two hundred fifty-one million, six hundred ninety-one thousand, one hundred thirteen".