31221816035309 has 2 divisors, whose sum is σ = 31221816035310. Its totient is φ = 31221816035308.

The previous prime is 31221816035239. The next prime is 31221816035327. The reversal of 31221816035309 is 90353061812213.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 16886732766409 + 14335083268900 = 4109347^2 + 3786170^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-31221816035309 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 31221816035309.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (31221816035359) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15610908017654 + 15610908017655.

It is an arithmetic number, because the mean of its divisors is an integer number (15610908017655).

Almost surely, 2^{31221816035309} is an apocalyptic number.

It is an amenable number.

31221816035309 is a deficient number, since it is larger than the sum of its proper divisors (1).

31221816035309 is an equidigital number, since it uses as much as digits as its factorization.

31221816035309 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 233280, while the sum is 44.

The spelling of 31221816035309 in words is "thirty-one trillion, two hundred twenty-one billion, eight hundred sixteen million, thirty-five thousand, three hundred nine".