231221251 has 4 divisors (see below), whose sum is σ = 237470512. Its totient is φ = 224971992.

The previous prime is 231221239. The next prime is 231221273. The reversal of 231221251 is 152122132.

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 231221251 - 2⁹ = 231220739 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (231221201) 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, 3124575 + ... + 3124648.

It is an arithmetic number, because the mean of its divisors is an integer number (59367628).

Almost surely, 2^231221251 is an apocalyptic number.

231221251 is a deficient number, since it is larger than the sum of its proper divisors (6249261).

231221251 is an equidigital number, since it uses as much as digits as its factorization.

231221251 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6249260.

The product of its digits is 240, while the sum is 19.

The square root of 231221251 is about 15205.9610350678. The cubic root of 231221251 is about 613.7750761487.

Adding to 231221251 its reverse (152122132), we get a palindrome (383343383).

The spelling of 231221251 in words is "two hundred thirty-one million, two hundred twenty-one thousand, two hundred fifty-one".