231312221321 has 2 divisors, whose sum is σ = 231312221322. Its totient is φ = 231312221320.

The previous prime is 231312221317. The next prime is 231312221353. The reversal of 231312221321 is 123122213132.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 118036222096 + 113275999225 = 343564^2 + 336565^2 .

It is a cyclic number.

It is not a de Polignac number, because 231312221321 - 2² = 231312221317 is a prime.

It is not a weakly prime, because it can be changed into another prime (231312221221) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 115656110660 + 115656110661.

It is an arithmetic number, because the mean of its divisors is an integer number (115656110661).

Almost surely, 2^231312221321 is an apocalyptic number.

It is an amenable number.

231312221321 is a deficient number, since it is larger than the sum of its proper divisors (1).

231312221321 is an equidigital number, since it uses as much as digits as its factorization.

231312221321 is an evil number, because the sum of its binary digits is even.

The product of its digits is 864, while the sum is 23.

Adding to 231312221321 its reverse (123122213132), we get a palindrome (354434434453).

The spelling of 231312221321 in words is "two hundred thirty-one billion, three hundred twelve million, two hundred twenty-one thousand, three hundred twenty-one".