18216845 has 4 divisors (see below), whose sum is σ = 21860220. Its totient is φ = 14573472.

The previous prime is 18216823. The next prime is 18216853. The reversal of 18216845 is 54861281.

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

It can be written as a sum of positive squares in 2 ways, for example, as 3455881 + 14760964 = 1859^2 + 3842^2 .

It is a cyclic number.

It is not a de Polignac number, because 18216845 - 2¹² = 18212749 is a prime.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1821680 + ... + 1821689.

It is an arithmetic number, because the mean of its divisors is an integer number (5465055).

Almost surely, 2^18216845 is an apocalyptic number.

It is an amenable number.

18216845 is a deficient number, since it is larger than the sum of its proper divisors (3643375).

18216845 is an equidigital number, since it uses as much as digits as its factorization.

18216845 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3643374.

The product of its digits is 15360, while the sum is 35.

The square root of 18216845 is about 4268.1196093830. The cubic root of 18216845 is about 263.1223389541.

The spelling of 18216845 in words is "eighteen million, two hundred sixteen thousand, eight hundred forty-five".