251231 has 2 divisors, whose sum is σ = 251232. Its totient is φ = 251230.

The previous prime is 251221. The next prime is 251233. The reversal of 251231 is 132152.

It is a happy number.

251231 is nontrivially palindromic in base 4.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 251231 - 2¹⁴ = 234847 is a prime.

It is a super-2 number, since 2×251231² = 126234030722, which contains 22 as substring.

Together with 251233, it forms a pair of twin primes.

It is a Chen prime.

It is an Ulam number.

It is a zygodrome in base 4.

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 251231.

It is not a weakly prime, because it can be changed into another prime (251233) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 125615 + 125616.

It is an arithmetic number, because the mean of its divisors is an integer number (125616).

2²⁵¹²³¹ is an apocalyptic number.

251231 is a deficient number, since it is larger than the sum of its proper divisors (1).

251231 is an equidigital number, since it uses as much as digits as its factorization.

251231 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 60, while the sum is 14.

The square root of 251231 is about 501.2294883584. The cubic root of 251231 is about 63.0992807685.

Adding to 251231 its reverse (132152), we get a palindrome (383383).

The spelling of 251231 in words is "two hundred fifty-one thousand, two hundred thirty-one".