20805321409 has 8 divisors (see below), whose sum is σ = 21155797152. Its totient is φ = 20457222240.

The previous prime is 20805321403. The next prime is 20805321503. The reversal of 20805321409 is 90412350802.

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 20805321409 - 2³ = 20805321401 is a prime.

It is a super-2 number, since 2×20805321409² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20805321401) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 576484 + ... + 611509.

It is an arithmetic number, because the mean of its divisors is an integer number (2644474644).

Almost surely, 2^20805321409 is an apocalyptic number.

It is an amenable number.

20805321409 is a deficient number, since it is larger than the sum of its proper divisors (350475743).

20805321409 is a wasteful number, since it uses less digits than its factorization.

20805321409 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1188287.

The product of its (nonzero) digits is 17280, while the sum is 34.

The spelling of 20805321409 in words is "twenty billion, eight hundred five million, three hundred twenty-one thousand, four hundred nine".