31331505061261 has 2 divisors, whose sum is σ = 31331505061262. Its totient is φ = 31331505061260.

The previous prime is 31331505061253. The next prime is 31331505061271. The reversal of 31331505061261 is 16216050513313.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 24423176204361 + 6908328856900 = 4941981^2 + 2628370^2 .

It is a cyclic number.

It is not a de Polignac number, because 31331505061261 - 2³ = 31331505061253 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 31331505061261.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (31331505061271) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15665752530630 + 15665752530631.

It is an arithmetic number, because the mean of its divisors is an integer number (15665752530631).

Almost surely, 2^{31331505061261} is an apocalyptic number.

It is an amenable number.

31331505061261 is a deficient number, since it is larger than the sum of its proper divisors (1).

31331505061261 is an equidigital number, since it uses as much as digits as its factorization.

31331505061261 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 48600, while the sum is 37.

Adding to 31331505061261 its reverse (16216050513313), we get a palindrome (47547555574574).

The spelling of 31331505061261 in words is "thirty-one trillion, three hundred thirty-one billion, five hundred five million, sixty-one thousand, two hundred sixty-one".