18909863 has 4 divisors (see below), whose sum is σ = 21611280. Its totient is φ = 16208448.

The previous prime is 18909853. The next prime is 18909901. The reversal of 18909863 is 36890981.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-18909863 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18909823) 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, 1350698 + ... + 1350711.

It is an arithmetic number, because the mean of its divisors is an integer number (5402820).

Almost surely, 2^18909863 is an apocalyptic number.

18909863 is a deficient number, since it is larger than the sum of its proper divisors (2701417).

18909863 is an equidigital number, since it uses as much as digits as its factorization.

18909863 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2701416.

The product of its (nonzero) digits is 93312, while the sum is 44.

The square root of 18909863 is about 4348.5472286730. The cubic root of 18909863 is about 266.4175278998.

The spelling of 18909863 in words is "eighteen million, nine hundred nine thousand, eight hundred sixty-three".