20503309 has 8 divisors (see below), whose sum is σ = 22016448. Its totient is φ = 19024320.

The previous prime is 20503279. The next prime is 20503313. The reversal of 20503309 is 90330502.

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 20503309 - 2¹³ = 20495117 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 20503309.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20503349) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 7287 + ... + 9700.

It is an arithmetic number, because the mean of its divisors is an integer number (2752056).

Almost surely, 2^20503309 is an apocalyptic number.

It is an amenable number.

20503309 is a deficient number, since it is larger than the sum of its proper divisors (1513139).

20503309 is a wasteful number, since it uses less digits than its factorization.

20503309 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 17075.

The product of its (nonzero) digits is 810, while the sum is 22.

The square root of 20503309 is about 4528.0579722437. The cubic root of 20503309 is about 273.6999085456.

The spelling of 20503309 in words is "twenty million, five hundred three thousand, three hundred nine".