31521410621 has 2 divisors, whose sum is σ = 31521410622. Its totient is φ = 31521410620.

The previous prime is 31521410587. The next prime is 31521410633. The reversal of 31521410621 is 12601412513.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 30803760100 + 717650521 = 175510^2 + 26789^2 .

It is a cyclic number.

It is not a de Polignac number, because 31521410621 - 2²⁶ = 31454301757 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (31521410651) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15760705310 + 15760705311.

It is an arithmetic number, because the mean of its divisors is an integer number (15760705311).

Almost surely, 2^31521410621 is an apocalyptic number.

It is an amenable number.

31521410621 is a deficient number, since it is larger than the sum of its proper divisors (1).

31521410621 is an equidigital number, since it uses as much as digits as its factorization.

31521410621 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1440, while the sum is 26.

The spelling of 31521410621 in words is "thirty-one billion, five hundred twenty-one million, four hundred ten thousand, six hundred twenty-one".