20479969982921 has 2 divisors, whose sum is σ = 20479969982922. Its totient is φ = 20479969982920.

The previous prime is 20479969982903. The next prime is 20479969983001. The reversal of 20479969982921 is 12928996997402.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 16857757872400 + 3622212110521 = 4105820^2 + 1903211^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20479969982921 is a prime.

It is not a weakly prime, because it can be changed into another prime (20479969982821) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10239984991460 + 10239984991461.

It is an arithmetic number, because the mean of its divisors is an integer number (10239984991461).

Almost surely, 2^{20479969982921} is an apocalyptic number.

It is an amenable number.

20479969982921 is a deficient number, since it is larger than the sum of its proper divisors (1).

20479969982921 is an equidigital number, since it uses as much as digits as its factorization.

20479969982921 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 634894848, while the sum is 77.

The spelling of 20479969982921 in words is "twenty trillion, four hundred seventy-nine billion, nine hundred sixty-nine million, nine hundred eighty-two thousand, nine hundred twenty-one".