18478109 has 8 divisors (see below), whose sum is σ = 20011992. Its totient is φ = 16960320.

The previous prime is 18478093. The next prime is 18478121. The reversal of 18478109 is 90187481.

It can be written as a sum of positive squares in 4 ways, for example, as 3694084 + 14784025 = 1922^2 + 3845^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 18478109 - 2⁴ = 18478093 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18478189) by changing a digit.

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 7 ways as a sum of consecutive naturals, for example, 1574 + ... + 6279.

It is an arithmetic number, because the mean of its divisors is an integer number (2501499).

Almost surely, 2^18478109 is an apocalyptic number.

It is an amenable number.

18478109 is a deficient number, since it is larger than the sum of its proper divisors (1533883).

18478109 is a wasteful number, since it uses less digits than its factorization.

18478109 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8047.

The product of its (nonzero) digits is 16128, while the sum is 38.

The square root of 18478109 is about 4298.6171032089. The cubic root of 18478109 is about 264.3742635140.

It can be divided in two parts, 18478 and 109, that multiplied together give a palindrome (2014102).

The spelling of 18478109 in words is "eighteen million, four hundred seventy-eight thousand, one hundred nine".