31251243421261 has 2 divisors, whose sum is σ = 31251243421262. Its totient is φ = 31251243421260.

The previous prime is 31251243421199. The next prime is 31251243421301. The reversal of 31251243421261 is 16212434215213.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 19809220070025 + 11442023351236 = 4450755^2 + 3382606^2 .

It is a cyclic number.

It is not a de Polignac number, because 31251243421261 - 2³¹ = 31249095937613 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 31251243421261.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (31251243491261) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15625621710630 + 15625621710631.

It is an arithmetic number, because the mean of its divisors is an integer number (15625621710631).

Almost surely, 2^{31251243421261} is an apocalyptic number.

It is an amenable number.

31251243421261 is a deficient number, since it is larger than the sum of its proper divisors (1).

31251243421261 is an equidigital number, since it uses as much as digits as its factorization.

31251243421261 is an evil number, because the sum of its binary digits is even.

The product of its digits is 69120, while the sum is 37.

Adding to 31251243421261 its reverse (16212434215213), we get a palindrome (47463677636474).

The spelling of 31251243421261 in words is "thirty-one trillion, two hundred fifty-one billion, two hundred forty-three million, four hundred twenty-one thousand, two hundred sixty-one".