21222121021 has 8 divisors (see below), whose sum is σ = 21258889344. Its totient is φ = 21185376240.

The previous prime is 21222120989. The next prime is 21222121049. The reversal of 21222121021 is 12012122212.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21222121021 - 2⁵ = 21222120989 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21222120986 and 21222121004.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21222121121) 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 in 7 ways as a sum of consecutive naturals, for example, 3085216 + ... + 3092086.

It is an arithmetic number, because the mean of its divisors is an integer number (2657361168).

Almost surely, 2^21222121021 is an apocalyptic number.

It is an amenable number.

21222121021 is a deficient number, since it is larger than the sum of its proper divisors (36768323).

21222121021 is an equidigital number, since it uses as much as digits as its factorization.

21222121021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11771.

The product of its (nonzero) digits is 64, while the sum is 16.

Adding to 21222121021 its reverse (12012122212), we get a palindrome (33234243233).

The spelling of 21222121021 in words is "twenty-one billion, two hundred twenty-two million, one hundred twenty-one thousand, twenty-one".