20001009 has 8 divisors (see below), whose sum is σ = 30477760. Its totient is φ = 11429136.

The previous prime is 20001001. The next prime is 20001019. The reversal of 20001009 is 90010002.

It is a happy number.

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

It is not a de Polignac number, because 20001009 - 2³ = 20001001 is a prime.

It is a super-2 number, since 2×20001009² = 800080722036162, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 20000985 and 20001003.

It is not an unprimeable number, because it can be changed into a prime (20001001) 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, 476194 + ... + 476235.

It is an arithmetic number, because the mean of its divisors is an integer number (3809720).

Almost surely, 2^20001009 is an apocalyptic number.

It is an amenable number.

20001009 is a deficient number, since it is larger than the sum of its proper divisors (10476751).

20001009 is an equidigital number, since it uses as much as digits as its factorization.

20001009 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 952439.

The product of its (nonzero) digits is 18, while the sum is 12.

The square root of 20001009 is about 4472.2487632063. The cubic root of 20001009 is about 271.4463263284.

The spelling of 20001009 in words is "twenty million, one thousand, nine".