22021000021 has 2 divisors, whose sum is σ = 22021000022. Its totient is φ = 22021000020.

The previous prime is 22020999991. The next prime is 22021000037. The reversal of 22021000021 is 12000012022.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 21323300625 + 697699396 = 146025^2 + 26414^2 .

It is a cyclic number.

It is not a de Polignac number, because 22021000021 - 2⁷ = 22020999893 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 22020999971 and 22021000007.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (22021000321) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 11010500010 + 11010500011.

It is an arithmetic number, because the mean of its divisors is an integer number (11010500011).

Almost surely, 2^22021000021 is an apocalyptic number.

It is an amenable number.

22021000021 is a deficient number, since it is larger than the sum of its proper divisors (1).

22021000021 is an equidigital number, since it uses as much as digits as its factorization.

22021000021 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 16, while the sum is 10.

Adding to 22021000021 its reverse (12000012022), we get a palindrome (34021012043).

The spelling of 22021000021 in words is "twenty-two billion, twenty-one million, twenty-one", and thus it is an aban number and an uban number.