231031251221 has 16 divisors (see below), whose sum is σ = 238878996480. Its totient is φ = 223317084480.

The previous prime is 231031251197. The next prime is 231031251223. The reversal of 231031251221 is 122152130132.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-231031251221 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (231031251223) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 12792620 + ... + 12810666.

It is an arithmetic number, because the mean of its divisors is an integer number (14929937280).

Almost surely, 2^231031251221 is an apocalyptic number.

It is an amenable number.

231031251221 is a deficient number, since it is larger than the sum of its proper divisors (7847745259).

231031251221 is a wasteful number, since it uses less digits than its factorization.

231031251221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 21724.

The product of its (nonzero) digits is 720, while the sum is 23.

Adding to 231031251221 its reverse (122152130132), we get a palindrome (353183381353).

The spelling of 231031251221 in words is "two hundred thirty-one billion, thirty-one million, two hundred fifty-one thousand, two hundred twenty-one".