18164645 has 4 divisors (see below), whose sum is σ = 21797580. Its totient is φ = 14531712.

The previous prime is 18164639. The next prime is 18164647. The reversal of 18164645 is 54646181.

It is a Cunningham number, because it is equal to 4262²+1.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 54646181 = 1973 ⋅27697.

It can be written as a sum of positive squares in 2 ways, for example, as 6543364 + 11621281 = 2558^2 + 3409^2 .

It is a cyclic number.

It is not a de Polignac number, because 18164645 - 2¹⁴ = 18148261 is a prime.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18164647) 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, 1816460 + ... + 1816469.

It is an arithmetic number, because the mean of its divisors is an integer number (5449395).

Almost surely, 2^18164645 is an apocalyptic number.

It is an amenable number.

18164645 is a deficient number, since it is larger than the sum of its proper divisors (3632935).

18164645 is an equidigital number, since it uses as much as digits as its factorization.

18164645 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3632934.

The product of its digits is 23040, while the sum is 35.

The square root of 18164645 is about 4262.0001173158. Note that the first 3 decimals coincide. The cubic root of 18164645 is about 262.8707746075.

The spelling of 18164645 in words is "eighteen million, one hundred sixty-four thousand, six hundred forty-five".