2001001209 has 4 divisors (see below), whose sum is σ = 2668001616. Its totient is φ = 1334000804.

The previous prime is 2001001183. The next prime is 2001001241. The reversal of 2001001209 is 9021001002.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 2001001209 - 2¹⁵ = 2000968441 is a prime.

It is not an unprimeable number, because it can be changed into a prime (2001001109) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 333500199 + ... + 333500204.

It is an arithmetic number, because the mean of its divisors is an integer number (667000404).

Almost surely, 2^2001001209 is an apocalyptic number.

It is an amenable number.

2001001209 is a deficient number, since it is larger than the sum of its proper divisors (667000407).

2001001209 is an equidigital number, since it uses as much as digits as its factorization.

2001001209 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 667000406.

The product of its (nonzero) digits is 36, while the sum is 15.

The square root of 2001001209 is about 44732.5520063410. The cubic root of 2001001209 is about 1260.1312555379.

The spelling of 2001001209 in words is "two billion, one million, one thousand, two hundred nine".