21220320109 has 2 divisors, whose sum is σ = 21220320110. Its totient is φ = 21220320108.

The previous prime is 21220320097. The next prime is 21220320151. The reversal of 21220320109 is 90102302212.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 21165885225 + 54434884 = 145485^2 + 7378^2 .

It is a cyclic number.

It is not a de Polignac number, because 21220320109 - 2¹¹ = 21220318061 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21220320109.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21920320109) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10610160054 + 10610160055.

It is an arithmetic number, because the mean of its divisors is an integer number (10610160055).

Almost surely, 2^21220320109 is an apocalyptic number.

It is an amenable number.

21220320109 is a deficient number, since it is larger than the sum of its proper divisors (1).

21220320109 is an equidigital number, since it uses as much as digits as its factorization.

21220320109 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 432, while the sum is 22.

The spelling of 21220320109 in words is "twenty-one billion, two hundred twenty million, three hundred twenty thousand, one hundred nine".