20000009 has 4 divisors (see below), whose sum is σ = 20327940. Its totient is φ = 19672080.

The previous prime is 20000003. The next prime is 20000023. The reversal of 20000009 is 90000002.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 595984 + 19404025 = 772^2 + 4405^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20000009 is a prime.

It is a Duffinian number.

20000009 is a modest number, since divided by 9 gives 2 as remainder.

It is not an unprimeable number, because it can be changed into a prime (20000003) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 163874 + ... + 163995.

It is an arithmetic number, because the mean of its divisors is an integer number (5081985).

Almost surely, 2^20000009 is an apocalyptic number.

It is an amenable number.

20000009 is a deficient number, since it is larger than the sum of its proper divisors (327931).

20000009 is an equidigital number, since it uses as much as digits as its factorization.

20000009 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 327930.

The product of its (nonzero) digits is 18, while the sum is 11.

The square root of 20000009 is about 4472.1369612301. The cubic root of 20000009 is about 271.4418023757.

Subtracting from 20000009 its product of nonzero digits (18), we obtain a palindrome (19999991).

Adding to 20000009 its reverse (90000002), we get a palindrome (110000011).

The spelling of 20000009 in words is "twenty million, nine", and thus it is an aban number and an uban number.