22021001921 has 2 divisors, whose sum is σ = 22021001922. Its totient is φ = 22021001920.

The previous prime is 22021001909. The next prime is 22021001923. The reversal of 22021001921 is 12910012022.

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., 19761330625 + 2259671296 = 140575^2 + 47536^2 .

It is a cyclic number.

It is not a de Polignac number, because 22021001921 - 2¹⁸ = 22020739777 is a prime.

Together with 22021001923, it forms a pair of twin primes.

It is a Chen prime.

It is a junction number, because it is equal to n+sod(n) for n = 22021001893 and 22021001902.

It is not a weakly prime, because it can be changed into another prime (22021001923) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 11010500960 + 11010500961.

It is an arithmetic number, because the mean of its divisors is an integer number (11010500961).

Almost surely, 2^22021001921 is an apocalyptic number.

It is an amenable number.

22021001921 is a deficient number, since it is larger than the sum of its proper divisors (1).

22021001921 is an equidigital number, since it uses as much as digits as its factorization.

22021001921 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 144, while the sum is 20.

Adding to 22021001921 its reverse (12910012022), we get a palindrome (34931013943).

The spelling of 22021001921 in words is "twenty-two billion, twenty-one million, one thousand, nine hundred twenty-one".