21220012120997 has 2 divisors, whose sum is σ = 21220012120998. Its totient is φ = 21220012120996.

The previous prime is 21220012120991. The next prime is 21220012121041. The reversal of 21220012120997 is 79902121002212.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 10781937019396 + 10438075101601 = 3283586^2 + 3230801^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21220012120997 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21220012120997.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21220012120991) 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, 10610006060498 + 10610006060499.

It is an arithmetic number, because the mean of its divisors is an integer number (10610006060499).

Almost surely, 2^{21220012120997} is an apocalyptic number.

It is an amenable number.

21220012120997 is a deficient number, since it is larger than the sum of its proper divisors (1).

21220012120997 is an equidigital number, since it uses as much as digits as its factorization.

21220012120997 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 18144, while the sum is 38.

The spelling of 21220012120997 in words is "twenty-one trillion, two hundred twenty billion, twelve million, one hundred twenty thousand, nine hundred ninety-seven".