2009121689 has 4 divisors (see below), whose sum is σ = 2031696180. Its totient is φ = 1986547200.

The previous prime is 2009121683. The next prime is 2009121703. The reversal of 2009121689 is 9861219002.

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 859369225 + 1149752464 = 29315^2 + 33908^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-2009121689 is a prime.

It is a super-2 number, since 2×2009121689² = 8073139922420425442, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (2009121683) 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, 11287112 + ... + 11287289.

It is an arithmetic number, because the mean of its divisors is an integer number (507924045).

Almost surely, 2^2009121689 is an apocalyptic number.

It is an amenable number.

2009121689 is a deficient number, since it is larger than the sum of its proper divisors (22574491).

2009121689 is an equidigital number, since it uses as much as digits as its factorization.

2009121689 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 22574490.

The product of its (nonzero) digits is 15552, while the sum is 38.

The square root of 2009121689 is about 44823.2271149680. The cubic root of 2009121689 is about 1261.8335799147.

The spelling of 2009121689 in words is "two billion, nine million, one hundred twenty-one thousand, six hundred eighty-nine".