18161803 has 4 divisors (see below), whose sum is σ = 19812888. Its totient is φ = 16510720.

The previous prime is 18161791. The next prime is 18161807. The reversal of 18161803 is 30816181.

It is a happy number.

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

It is a cyclic number.

It is not a de Polignac number, because 18161803 - 2⁵ = 18161771 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (18161807) 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, 825526 + ... + 825547.

It is an arithmetic number, because the mean of its divisors is an integer number (4953222).

Almost surely, 2^18161803 is an apocalyptic number.

18161803 is a deficient number, since it is larger than the sum of its proper divisors (1651085).

18161803 is a wasteful number, since it uses less digits than its factorization.

18161803 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1651084.

The product of its (nonzero) digits is 1152, while the sum is 28.

The square root of 18161803 is about 4261.6666927389. Note that the first 4 decimals coincide. The cubic root of 18161803 is about 262.8570645000.

Adding to 18161803 its reverse (30816181), we get a palindrome (48977984).

The spelling of 18161803 in words is "eighteen million, one hundred sixty-one thousand, eight hundred three".