21809096809 has 8 divisors (see below), whose sum is σ = 22564624320. Its totient is φ = 21053802000.

The previous prime is 21809096801. The next prime is 21809096863. The reversal of 21809096809 is 90869090812.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21809096809 - 2³ = 21809096801 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21809096801) 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 in 7 ways as a sum of consecutive naturals, for example, 144534 + ... + 253984.

It is an arithmetic number, because the mean of its divisors is an integer number (2820578040).

Almost surely, 2^21809096809 is an apocalyptic number.

21809096809 is a gapful number since it is divisible by the number (29) formed by its first and last digit.

It is an amenable number.

21809096809 is a deficient number, since it is larger than the sum of its proper divisors (755527511).

21809096809 is a wasteful number, since it uses less digits than its factorization.

21809096809 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 116351.

The product of its (nonzero) digits is 559872, while the sum is 52.

The spelling of 21809096809 in words is "twenty-one billion, eight hundred nine million, ninety-six thousand, eight hundred nine".