18728563 has 8 divisors (see below), whose sum is σ = 21573632. Its totient is φ = 15925896.

The previous prime is 18728561. The next prime is 18728569. The reversal of 18728563 is 36582781.

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

It is not a de Polignac number, because 18728563 - 2¹ = 18728561 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (18728561) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 9645 + ... + 11422.

It is an arithmetic number, because the mean of its divisors is an integer number (2696704).

Almost surely, 2^18728563 is an apocalyptic number.

18728563 is a deficient number, since it is larger than the sum of its proper divisors (2845069).

18728563 is a wasteful number, since it uses less digits than its factorization.

18728563 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 21201.

The product of its digits is 80640, while the sum is 40.

The square root of 18728563 is about 4327.6509794576. The cubic root of 18728563 is about 265.5633583007.

It can be divided in two parts, 18728 and 563, that added together give a palindrome (19291).

The spelling of 18728563 in words is "eighteen million, seven hundred twenty-eight thousand, five hundred sixty-three".