21920320109 has 2 divisors, whose sum is σ = 21920320110. Its totient is φ = 21920320108.

The previous prime is 21920320099. The next prime is 21920320117. The reversal of 21920320109 is 90102302912.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 12159472900 + 9760847209 = 110270^2 + 98797^2 .

It is a cyclic number.

It is not a de Polignac number, because 21920320109 - 2³² = 17625352813 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21920380109) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10960160054 + 10960160055.

It is an arithmetic number, because the mean of its divisors is an integer number (10960160055).

Almost surely, 2^21920320109 is an apocalyptic number.

It is an amenable number.

21920320109 is a deficient number, since it is larger than the sum of its proper divisors (1).

21920320109 is an equidigital number, since it uses as much as digits as its factorization.

21920320109 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1944, while the sum is 29.

The spelling of 21920320109 in words is "twenty-one billion, nine hundred twenty million, three hundred twenty thousand, one hundred nine".