20215972681321 has 2 divisors, whose sum is σ = 20215972681322. Its totient is φ = 20215972681320.

The previous prime is 20215972681273. The next prime is 20215972681459. The reversal of 20215972681321 is 12318627951202.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 17712650649600 + 2503322031721 = 4208640^2 + 1582189^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20215972681321 is a prime.

It is not a weakly prime, because it can be changed into another prime (20215972681621) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10107986340660 + 10107986340661.

It is an arithmetic number, because the mean of its divisors is an integer number (10107986340661).

Almost surely, 2^{20215972681321} is an apocalyptic number.

It is an amenable number.

20215972681321 is a deficient number, since it is larger than the sum of its proper divisors (1).

20215972681321 is an equidigital number, since it uses as much as digits as its factorization.

20215972681321 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 725760, while the sum is 49.

The spelling of 20215972681321 in words is "twenty trillion, two hundred fifteen billion, nine hundred seventy-two million, six hundred eighty-one thousand, three hundred twenty-one".