18120545 has 4 divisors (see below), whose sum is σ = 21744660. Its totient is φ = 14496432.

The previous prime is 18120517. The next prime is 18120559. The reversal of 18120545 is 54502181.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 54502181 = 6221 ⋅8761.

It can be written as a sum of positive squares in 2 ways, for example, as 2808976 + 15311569 = 1676^2 + 3913^2 .

It is a cyclic number.

It is not a de Polignac number, because 18120545 - 2²⁰ = 17071969 is a prime.

It is a Curzon number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1812050 + ... + 1812059.

It is an arithmetic number, because the mean of its divisors is an integer number (5436165).

Almost surely, 2^18120545 is an apocalyptic number.

It is an amenable number.

18120545 is a deficient number, since it is larger than the sum of its proper divisors (3624115).

18120545 is an equidigital number, since it uses as much as digits as its factorization.

18120545 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3624114.

The product of its (nonzero) digits is 1600, while the sum is 26.

The square root of 18120545 is about 4256.8233461115. The cubic root of 18120545 is about 262.6578702667.

The spelling of 18120545 in words is "eighteen million, one hundred twenty thousand, five hundred forty-five".