21022202021 has 2 divisors, whose sum is σ = 21022202022. Its totient is φ = 21022202020.

The previous prime is 21022201987. The next prime is 21022202029. The reversal of 21022202021 is 12020222012.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 20962696225 + 59505796 = 144785^2 + 7714^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21022202021 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21022201987 and 21022202005.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21022202029) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10511101010 + 10511101011.

It is an arithmetic number, because the mean of its divisors is an integer number (10511101011).

Almost surely, 2^21022202021 is an apocalyptic number.

It is an amenable number.

21022202021 is a deficient number, since it is larger than the sum of its proper divisors (1).

21022202021 is an equidigital number, since it uses as much as digits as its factorization.

21022202021 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 64, while the sum is 14.

Adding to 21022202021 its reverse (12020222012), we get a palindrome (33042424033).

The spelling of 21022202021 in words is "twenty-one billion, twenty-two million, two hundred two thousand, twenty-one".