31628215621 has 2 divisors, whose sum is σ = 31628215622. Its totient is φ = 31628215620.

The previous prime is 31628215529. The next prime is 31628215631. The reversal of 31628215621 is 12651282613.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 18674589025 + 12953626596 = 136655^2 + 113814^2 .

It is a cyclic number.

It is not a de Polignac number, because 31628215621 - 2¹⁷ = 31628084549 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (31628215631) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15814107810 + 15814107811.

It is an arithmetic number, because the mean of its divisors is an integer number (15814107811).

Almost surely, 2^31628215621 is an apocalyptic number.

It is an amenable number.

31628215621 is a deficient number, since it is larger than the sum of its proper divisors (1).

31628215621 is an equidigital number, since it uses as much as digits as its factorization.

31628215621 is an evil number, because the sum of its binary digits is even.

The product of its digits is 34560, while the sum is 37.

The spelling of 31628215621 in words is "thirty-one billion, six hundred twenty-eight million, two hundred fifteen thousand, six hundred twenty-one".