21211002009997 has 2 divisors, whose sum is σ = 21211002009998. Its totient is φ = 21211002009996.

The previous prime is 21211002009949. The next prime is 21211002010019. The reversal of 21211002009997 is 79990020011212.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 20896472842756 + 314529167241 = 4571266^2 + 560829^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21211002009997 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21211002009697) 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, 10605501004998 + 10605501004999.

It is an arithmetic number, because the mean of its divisors is an integer number (10605501004999).

Almost surely, 2^{21211002009997} is an apocalyptic number.

It is an amenable number.

21211002009997 is a deficient number, since it is larger than the sum of its proper divisors (1).

21211002009997 is an equidigital number, since it uses as much as digits as its factorization.

21211002009997 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 40824, while the sum is 43.

The spelling of 21211002009997 in words is "twenty-one trillion, two hundred eleven billion, two million, nine thousand, nine hundred ninety-seven".