20518203 has 4 divisors (see below), whose sum is σ = 27357608. Its totient is φ = 13678800.

The previous prime is 20518193. The next prime is 20518217. The reversal of 20518203 is 30281502.

It is a semiprime because it is the product of two primes.

It is not a de Polignac number, because 20518203 - 2⁸ = 20517947 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 20518203.

It is not an unprimeable number, because it can be changed into a prime (20518243) 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 3 ways as a sum of consecutive naturals, for example, 3419698 + ... + 3419703.

It is an arithmetic number, because the mean of its divisors is an integer number (6839402).

Almost surely, 2^20518203 is an apocalyptic number.

20518203 is a deficient number, since it is larger than the sum of its proper divisors (6839405).

20518203 is an equidigital number, since it uses as much as digits as its factorization.

20518203 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6839404.

The product of its (nonzero) digits is 480, while the sum is 21.

The square root of 20518203 is about 4529.7023080993. The cubic root of 20518203 is about 273.7661661394.

Adding to 20518203 its reverse (30281502), we get a palindrome (50799705).

The spelling of 20518203 in words is "twenty million, five hundred eighteen thousand, two hundred three".