21020022209 has 2 divisors, whose sum is σ = 21020022210. Its totient is φ = 21020022208.

The previous prime is 21020022187. The next prime is 21020022241. The reversal of 21020022209 is 90222002012.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 11165092225 + 9854929984 = 105665^2 + 99272^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21020022209 is a prime.

It is not a weakly prime, because it can be changed into another prime (21020028209) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10510011104 + 10510011105.

It is an arithmetic number, because the mean of its divisors is an integer number (10510011105).

Almost surely, 2^21020022209 is an apocalyptic number.

It is an amenable number.

21020022209 is a deficient number, since it is larger than the sum of its proper divisors (1).

21020022209 is an equidigital number, since it uses as much as digits as its factorization.

21020022209 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 288, while the sum is 20.

The spelling of 21020022209 in words is "twenty-one billion, twenty million, twenty-two thousand, two hundred nine".