20557503 has 8 divisors (see below), whose sum is σ = 30455600. Its totient is φ = 13704984.

The previous prime is 20557489. The next prime is 20557507. The reversal of 20557503 is 30575502.

It is not a de Polignac number, because 20557503 - 2¹⁰ = 20556479 is a prime.

It is a super-2 number, since 2×20557503² = 845221859190018, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (27), and also a Moran number because the ratio is a prime number: 761389 = 20557503 / (2 + 0 + 5 + 5 + 7 + 5 + 0 + 3).

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20557507) 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, 380668 + ... + 380721.

It is an arithmetic number, because the mean of its divisors is an integer number (3806950).

Almost surely, 2^20557503 is an apocalyptic number.

20557503 is a deficient number, since it is larger than the sum of its proper divisors (9898097).

20557503 is an equidigital number, since it uses as much as digits as its factorization.

20557503 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 761398 (or 761392 counting only the distinct ones).

The product of its (nonzero) digits is 5250, while the sum is 27.

The square root of 20557503 is about 4534.0382662699. The cubic root of 20557503 is about 273.9408427174.

The spelling of 20557503 in words is "twenty million, five hundred fifty-seven thousand, five hundred three".