20021321309993 has 2 divisors, whose sum is σ = 20021321309994. Its totient is φ = 20021321309992.

The previous prime is 20021321309917. The next prime is 20021321310013. The reversal of 20021321309993 is 39990312312002.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 13953907953049 + 6067413356944 = 3735493^2 + 2463212^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20021321309993 is a prime.

It is not a weakly prime, because it can be changed into another prime (20021321309893) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10010660654996 + 10010660654997.

It is an arithmetic number, because the mean of its divisors is an integer number (10010660654997).

Almost surely, 2^{20021321309993} is an apocalyptic number.

It is an amenable number.

20021321309993 is a deficient number, since it is larger than the sum of its proper divisors (1).

20021321309993 is an equidigital number, since it uses as much as digits as its factorization.

20021321309993 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 157464, while the sum is 44.

The spelling of 20021321309993 in words is "twenty trillion, twenty-one billion, three hundred twenty-one million, three hundred nine thousand, nine hundred ninety-three".