31564606261 has 2 divisors, whose sum is σ = 31564606262. Its totient is φ = 31564606260.

The previous prime is 31564606259. The next prime is 31564606267. The reversal of 31564606261 is 16260646513.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 30208525636 + 1356080625 = 173806^2 + 36825^2 .

It is a cyclic number.

It is not a de Polignac number, because 31564606261 - 2¹ = 31564606259 is a prime.

Together with 31564606259, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (31564606267) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15782303130 + 15782303131.

It is an arithmetic number, because the mean of its divisors is an integer number (15782303131).

Almost surely, 2^31564606261 is an apocalyptic number.

It is an amenable number.

31564606261 is a deficient number, since it is larger than the sum of its proper divisors (1).

31564606261 is an equidigital number, since it uses as much as digits as its factorization.

31564606261 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 155520, while the sum is 40.

The spelling of 31564606261 in words is "thirty-one billion, five hundred sixty-four million, six hundred six thousand, two hundred sixty-one".