21212020002221 has 4 divisors (see below), whose sum is σ = 22134281741472. Its totient is φ = 20289758262972.

The previous prime is 21212020002193. The next prime is 21212020002227. The reversal of 21212020002221 is 12220002021212.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 21212020002221 - 2¹⁰ = 21212020001197 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 21212020002221.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21212020002227) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 461130869591 + ... + 461130869636.

It is an arithmetic number, because the mean of its divisors is an integer number (5533570435368).

Almost surely, 2^{21212020002221} is an apocalyptic number.

It is an amenable number.

21212020002221 is a deficient number, since it is larger than the sum of its proper divisors (922261739251).

21212020002221 is an equidigital number, since it uses as much as digits as its factorization.

21212020002221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 922261739250.

The product of its (nonzero) digits is 128, while the sum is 17.

Adding to 21212020002221 its reverse (12220002021212), we get a palindrome (33432022023433).

The spelling of 21212020002221 in words is "twenty-one trillion, two hundred twelve billion, twenty million, two thousand, two hundred twenty-one".