31131252121 has 2 divisors, whose sum is σ = 31131252122. Its totient is φ = 31131252120.

The previous prime is 31131252059. The next prime is 31131252161. The reversal of 31131252121 is 12125213113.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 23353952400 + 7777299721 = 152820^2 + 88189^2 .

It is a cyclic number.

It is not a de Polignac number, because 31131252121 - 2⁹ = 31131251609 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 31131252092 and 31131252101.

It is not a weakly prime, because it can be changed into another prime (31131252161) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15565626060 + 15565626061.

It is an arithmetic number, because the mean of its divisors is an integer number (15565626061).

Almost surely, 2^31131252121 is an apocalyptic number.

It is an amenable number.

31131252121 is a deficient number, since it is larger than the sum of its proper divisors (1).

31131252121 is an equidigital number, since it uses as much as digits as its factorization.

31131252121 is an evil number, because the sum of its binary digits is even.

The product of its digits is 360, while the sum is 22.

Adding to 31131252121 its reverse (12125213113), we get a palindrome (43256465234).

The spelling of 31131252121 in words is "thirty-one billion, one hundred thirty-one million, two hundred fifty-two thousand, one hundred twenty-one".