18981803 has 4 divisors (see below), whose sum is σ = 18992088. Its totient is φ = 18971520.

The previous prime is 18981773. The next prime is 18981821. The reversal of 18981803 is 30818981.

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: 30818981 = 47 ⋅655723.

It is a cyclic number.

It is not a de Polignac number, because 18981803 - 2¹⁰ = 18980779 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (18987803) 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, 1526 + ... + 6347.

It is an arithmetic number, because the mean of its divisors is an integer number (4748022).

Almost surely, 2^18981803 is an apocalyptic number.

18981803 is a deficient number, since it is larger than the sum of its proper divisors (10285).

18981803 is an equidigital number, since it uses as much as digits as its factorization.

18981803 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10284.

The product of its (nonzero) digits is 13824, while the sum is 38.

The square root of 18981803 is about 4356.8111044662. The cubic root of 18981803 is about 266.7549501097.

The spelling of 18981803 in words is "eighteen million, nine hundred eighty-one thousand, eight hundred three".