20903609 has 8 divisors (see below), whose sum is σ = 21156000. Its totient is φ = 20653056.

The previous prime is 20903593. The next prime is 20903621. The reversal of 20903609 is 90630902.

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

It is a cyclic number.

It is not a de Polignac number, because 20903609 - 2⁴ = 20903593 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20903689) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 41642 + ... + 42140.

It is an arithmetic number, because the mean of its divisors is an integer number (2644500).

Almost surely, 2^20903609 is an apocalyptic number.

It is an amenable number.

20903609 is a deficient number, since it is larger than the sum of its proper divisors (252391).

20903609 is a wasteful number, since it uses less digits than its factorization.

20903609 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 919.

The product of its (nonzero) digits is 2916, while the sum is 29.

The square root of 20903609 is about 4572.0464783289. The cubic root of 20903609 is about 275.4696503579.

It can be divided in two parts, 20903 and 609, that added together give a palindrome (21512).

The spelling of 20903609 in words is "twenty million, nine hundred three thousand, six hundred nine".