22000000021 has 2 divisors, whose sum is σ = 22000000022. Its totient is φ = 22000000020.

The previous prime is 22000000007. The next prime is 22000000031. The reversal of 22000000021 is 12000000022.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 20284880625 + 1715119396 = 142425^2 + 41414^2 .

It is a cyclic number.

It is not a de Polignac number, because 22000000021 - 2⁷ = 21999999893 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21999999950 and 22000000013.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (22000000031) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 11000000010 + 11000000011.

It is an arithmetic number, because the mean of its divisors is an integer number (11000000011).

Almost surely, 2^22000000021 is an apocalyptic number.

It is an amenable number.

22000000021 is a deficient number, since it is larger than the sum of its proper divisors (1).

22000000021 is an equidigital number, since it uses as much as digits as its factorization.

22000000021 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 8, while the sum is 7.

Adding to 22000000021 its reverse (12000000022), we get a palindrome (34000000043).

Subtracting from 22000000021 its reverse (12000000022), we obtain a palindrome (9999999999).

The spelling of 22000000021 in words is "twenty-two billion, twenty-one", and thus it is an aban number and an uban number.