251642231 has 2 divisors, whose sum is σ = 251642232. Its totient is φ = 251642230.

The previous prime is 251642227. The next prime is 251642233. The reversal of 251642231 is 132246152.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 251642231 - 2² = 251642227 is a prime.

It is a super-2 number, since 2×251642231² = 126647624845314722, which contains 22 as substring.

Together with 251642233, it forms a pair of twin primes.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 251642231.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (251642233) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 125821115 + 125821116.

It is an arithmetic number, because the mean of its divisors is an integer number (125821116).

Almost surely, 2^251642231 is an apocalyptic number.

251642231 is a deficient number, since it is larger than the sum of its proper divisors (1).

251642231 is an equidigital number, since it uses as much as digits as its factorization.

251642231 is an evil number, because the sum of its binary digits is even.

The product of its digits is 2880, while the sum is 26.

The square root of 251642231 is about 15863.2351996684. The cubic root of 251642231 is about 631.3369031616.

Adding to 251642231 its reverse (132246152), we get a palindrome (383888383).

The spelling of 251642231 in words is "two hundred fifty-one million, six hundred forty-two thousand, two hundred thirty-one".