231312121 has 2 divisors, whose sum is σ = 231312122. Its totient is φ = 231312120.

The previous prime is 231312113. The next prime is 231312139. The reversal of 231312121 is 121213132.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 211411600 + 19900521 = 14540^2 + 4461^2 .

It is a cyclic number.

It is not a de Polignac number, because 231312121 - 2³ = 231312113 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 231312095 and 231312104.

It is not a weakly prime, because it can be changed into another prime (231312161) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 115656060 + 115656061.

It is an arithmetic number, because the mean of its divisors is an integer number (115656061).

Almost surely, 2^231312121 is an apocalyptic number.

It is an amenable number.

231312121 is a deficient number, since it is larger than the sum of its proper divisors (1).

231312121 is an equidigital number, since it uses as much as digits as its factorization.

231312121 is an evil number, because the sum of its binary digits is even.

The product of its digits is 72, while the sum is 16.

The square root of 231312121 is about 15208.9487144904. The cubic root of 231312121 is about 613.8554701957.

Adding to 231312121 its reverse (121213132), we get a palindrome (352525253).

It can be divided in two parts, 23131 and 2121, that added together give a palindrome (25252).

The spelling of 231312121 in words is "two hundred thirty-one million, three hundred twelve thousand, one hundred twenty-one".