20005509 has 16 divisors (see below), whose sum is σ = 27855360. Its totient is φ = 12756480.

The previous prime is 20005507. The next prime is 20005511. The reversal of 20005509 is 90550002.

It is an interprime number because it is at equal distance from previous prime (20005507) and next prime (20005511).

It is not a de Polignac number, because 20005509 - 2¹ = 20005507 is a prime.

It is a super-3 number, since 3×20005509³ (a number of 23 digits) contains 333 as substring.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20005501) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 7069 + ... + 9485.

It is an arithmetic number, because the mean of its divisors is an integer number (1740960).

Almost surely, 2^20005509 is an apocalyptic number.

It is an amenable number.

20005509 is a deficient number, since it is larger than the sum of its proper divisors (7849851).

20005509 is a wasteful number, since it uses less digits than its factorization.

20005509 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2540.

The product of its (nonzero) digits is 450, while the sum is 21.

The square root of 20005509 is about 4472.7518375157. The cubic root of 20005509 is about 271.4666822493.

The spelling of 20005509 in words is "twenty million, five thousand, five hundred nine".