19872418 has 4 divisors (see below), whose sum is σ = 29808630. Its totient is φ = 9936208.

The previous prime is 19872389. The next prime is 19872421. The reversal of 19872418 is 81427891.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 81427891 = 5503 ⋅14797.

It can be written as a sum of positive squares in only one way, i.e., 19864849 + 7569 = 4457^2 + 87^2 .

It is a Smith number, since the sum of its digits (40) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax 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 as a sum of consecutive naturals, namely, 4968103 + ... + 4968106.

Almost surely, 2^19872418 is an apocalyptic number.

19872418 is a deficient number, since it is larger than the sum of its proper divisors (9936212).

19872418 is an equidigital number, since it uses as much as digits as its factorization.

19872418 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9936211.

The product of its digits is 32256, while the sum is 40.

The square root of 19872418 is about 4457.8490328857. The cubic root of 19872418 is about 270.8633452711.

The spelling of 19872418 in words is "nineteen million, eight hundred seventy-two thousand, four hundred eighteen".