6691220909 has 2 divisors, whose sum is σ = 6691220910. Its totient is φ = 6691220908.

The previous prime is 6691220891. The next prime is 6691220911. The reversal of 6691220909 is 9090221966.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 5094818884 + 1596402025 = 71378^2 + 39955^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-6691220909 is a prime.

Together with 6691220911, it forms a pair of twin primes.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 6691220909.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (6691220989) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3345610454 + 3345610455.

It is an arithmetic number, because the mean of its divisors is an integer number (3345610455).

Almost surely, 2^6691220909 is an apocalyptic number.

It is an amenable number.

6691220909 is a deficient number, since it is larger than the sum of its proper divisors (1).

6691220909 is an equidigital number, since it uses as much as digits as its factorization.

6691220909 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 104976, while the sum is 44.

The square root of 6691220909 is about 81799.8833067627. The cubic root of 6691220909 is about 1884.3798694182.

The spelling of 6691220909 in words is "six billion, six hundred ninety-one million, two hundred twenty thousand, nine hundred nine".