31223310821 has 2 divisors, whose sum is σ = 31223310822. Its totient is φ = 31223310820.

The previous prime is 31223310739. The next prime is 31223310823. The reversal of 31223310821 is 12801332213.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 22890177025 + 8333133796 = 151295^2 + 91286^2 .

It is a cyclic number.

It is not a de Polignac number, because 31223310821 - 2³⁰ = 30149568997 is a prime.

Together with 31223310823, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (31223310823) 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, 15611655410 + 15611655411.

It is an arithmetic number, because the mean of its divisors is an integer number (15611655411).

Almost surely, 2^31223310821 is an apocalyptic number.

It is an amenable number.

31223310821 is a deficient number, since it is larger than the sum of its proper divisors (1).

31223310821 is an equidigital number, since it uses as much as digits as its factorization.

31223310821 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1728, while the sum is 26.

The spelling of 31223310821 in words is "thirty-one billion, two hundred twenty-three million, three hundred ten thousand, eight hundred twenty-one".