251312231 has 4 divisors (see below), whose sum is σ = 259978200. Its totient is φ = 242646264.

The previous prime is 251312227. The next prime is 251312267. The reversal of 251312231 is 132213152.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 251312231 - 2² = 251312227 is a prime.

It is a super-3 number, since 3×251312231³ (a number of 26 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (251312531) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4332941 + ... + 4332998.

It is an arithmetic number, because the mean of its divisors is an integer number (64994550).

Almost surely, 2^251312231 is an apocalyptic number.

251312231 is a deficient number, since it is larger than the sum of its proper divisors (8665969).

251312231 is an equidigital number, since it uses as much as digits as its factorization.

251312231 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8665968.

The product of its digits is 360, while the sum is 20.

The square root of 251312231 is about 15852.8303782006. The cubic root of 251312231 is about 631.0608070608.

Adding to 251312231 its reverse (132213152), we get a palindrome (383525383).

The spelling of 251312231 in words is "two hundred fifty-one million, three hundred twelve thousand, two hundred thirty-one".