21022102009 has 2 divisors, whose sum is σ = 21022102010. Its totient is φ = 21022102008.

The previous prime is 21022101983. The next prime is 21022102019. The reversal of 21022102009 is 90020122012.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 21016880784 + 5221225 = 144972^2 + 2285^2 .

It is a cyclic number.

It is not a de Polignac number, because 21022102009 - 2¹⁹ = 21021577721 is a prime.

It is not a weakly prime, because it can be changed into another prime (21022102019) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10511051004 + 10511051005.

It is an arithmetic number, because the mean of its divisors is an integer number (10511051005).

Almost surely, 2^21022102009 is an apocalyptic number.

It is an amenable number.

21022102009 is a deficient number, since it is larger than the sum of its proper divisors (1).

21022102009 is an equidigital number, since it uses as much as digits as its factorization.

21022102009 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 19.

The spelling of 21022102009 in words is "twenty-one billion, twenty-two million, one hundred two thousand, nine".