31221029993 has 2 divisors, whose sum is σ = 31221029994. Its totient is φ = 31221029992.

The previous prime is 31221029981. The next prime is 31221030023. The reversal of 31221029993 is 39992012213.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 27719586064 + 3501443929 = 166492^2 + 59173^2 .

It is a cyclic number.

It is not a de Polignac number, because 31221029993 - 2¹⁴ = 31221013609 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 31221029993.

It is not a weakly prime, because it can be changed into another prime (31221025993) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15610514996 + 15610514997.

It is an arithmetic number, because the mean of its divisors is an integer number (15610514997).

Almost surely, 2^31221029993 is an apocalyptic number.

It is an amenable number.

31221029993 is a deficient number, since it is larger than the sum of its proper divisors (1).

31221029993 is an equidigital number, since it uses as much as digits as its factorization.

31221029993 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 52488, while the sum is 41.

The spelling of 31221029993 in words is "thirty-one billion, two hundred twenty-one million, twenty-nine thousand, nine hundred ninety-three".