21020220020209 has 2 divisors, whose sum is σ = 21020220020210. Its totient is φ = 21020220020208.

The previous prime is 21020220020167. The next prime is 21020220020221. The reversal of 21020220020209 is 90202002202012.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 19468638379584 + 1551581640625 = 4412328^2 + 1245625^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21020220020209 is a prime.

It is a super-3 number, since 3×21020220020209³ (a number of 41 digits) contains 333 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 21020220020209.

It is not a weakly prime, because it can be changed into another prime (21020220020249) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10510110010104 + 10510110010105.

It is an arithmetic number, because the mean of its divisors is an integer number (10510110010105).

Almost surely, 2^{21020220020209} is an apocalyptic number.

It is an amenable number.

21020220020209 is a deficient number, since it is larger than the sum of its proper divisors (1).

21020220020209 is an equidigital number, since it uses as much as digits as its factorization.

21020220020209 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 576, while the sum is 22.

The spelling of 21020220020209 in words is "twenty-one trillion, twenty billion, two hundred twenty million, twenty thousand, two hundred nine".