18864563 has 4 divisors (see below), whose sum is σ = 18876000. Its totient is φ = 18853128.

The previous prime is 18864557. The next prime is 18864569. The reversal of 18864563 is 36546881.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length, and also an emirpimes, since its reverse is a distinct semiprime: 36546881 = 7 ⋅5220983.

It is an interprime number because it is at equal distance from previous prime (18864557) and next prime (18864569).

It is a cyclic number.

It is not a de Polignac number, because 18864563 - 2¹² = 18860467 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 18864563.

It is not an unprimeable number, because it can be changed into a prime (18864569) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2720 + ... + 6717.

It is an arithmetic number, because the mean of its divisors is an integer number (4719000).

Almost surely, 2^18864563 is an apocalyptic number.

18864563 is a deficient number, since it is larger than the sum of its proper divisors (11437).

18864563 is an equidigital number, since it uses as much as digits as its factorization.

18864563 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11436.

The product of its digits is 138240, while the sum is 41.

The square root of 18864563 is about 4343.3354694290. The cubic root of 18864563 is about 266.2046167146.

The spelling of 18864563 in words is "eighteen million, eight hundred sixty-four thousand, five hundred sixty-three".