21112220212021 has 2 divisors, whose sum is σ = 21112220212022. Its totient is φ = 21112220212020.

The previous prime is 21112220212007. The next prime is 21112220212087. The reversal of 21112220212021 is 12021202221112.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 21009893159025 + 102327052996 = 4583655^2 + 319886^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21112220212021 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21112220212021.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21112220222021) 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, 10556110106010 + 10556110106011.

It is an arithmetic number, because the mean of its divisors is an integer number (10556110106011).

Almost surely, 2^{21112220212021} is an apocalyptic number.

It is an amenable number.

21112220212021 is a deficient number, since it is larger than the sum of its proper divisors (1).

21112220212021 is an equidigital number, since it uses as much as digits as its factorization.

21112220212021 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 128, while the sum is 19.

Adding to 21112220212021 its reverse (12021202221112), we get a palindrome (33133422433133).

The spelling of 21112220212021 in words is "twenty-one trillion, one hundred twelve billion, two hundred twenty million, two hundred twelve thousand, twenty-one".