31131252161 has 2 divisors, whose sum is σ = 31131252162. Its totient is φ = 31131252160.

The previous prime is 31131252121. The next prime is 31131252167. The reversal of 31131252161 is 16125213113.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 15890115136 + 15241137025 = 126056^2 + 123455^2 .

It is a cyclic number.

It is not a de Polignac number, because 31131252161 - 2¹⁴ = 31131235777 is a prime.

It is a super-2 number, since 2×31131252161² (a number of 22 digits) contains 22 as substring.

It is a Sophie Germain prime.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 31131252161.

It is not a weakly prime, because it can be changed into another prime (31131252167) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15565626080 + 15565626081.

It is an arithmetic number, because the mean of its divisors is an integer number (15565626081).

Almost surely, 2^31131252161 is an apocalyptic number.

It is an amenable number.

31131252161 is a deficient number, since it is larger than the sum of its proper divisors (1).

31131252161 is an equidigital number, since it uses as much as digits as its factorization.

31131252161 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1080, while the sum is 26.

Adding to 31131252161 its reverse (16125213113), we get a palindrome (47256465274).

The spelling of 31131252161 in words is "thirty-one billion, one hundred thirty-one million, two hundred fifty-two thousand, one hundred sixty-one".