21222031021 has 2 divisors, whose sum is σ = 21222031022. Its totient is φ = 21222031020.

The previous prime is 21222031009. The next prime is 21222031037. The reversal of 21222031021 is 12013022212.

It is a happy number.

It is an a-pointer prime, because the next prime (21222031037) can be obtained adding 21222031021 to its sum of digits (16).

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 16150597225 + 5071433796 = 127085^2 + 71214^2 .

It is a cyclic number.

It is not a de Polignac number, because 21222031021 - 2⁵ = 21222030989 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21222030986 and 21222031004.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21222031001) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10611015510 + 10611015511.

It is an arithmetic number, because the mean of its divisors is an integer number (10611015511).

Almost surely, 2^21222031021 is an apocalyptic number.

It is an amenable number.

21222031021 is a deficient number, since it is larger than the sum of its proper divisors (1).

21222031021 is an equidigital number, since it uses as much as digits as its factorization.

21222031021 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 96, while the sum is 16.

Adding to 21222031021 its reverse (12013022212), we get a palindrome (33235053233).

The spelling of 21222031021 in words is "twenty-one billion, two hundred twenty-two million, thirty-one thousand, twenty-one".