18985478 has 4 divisors (see below), whose sum is σ = 28478220. Its totient is φ = 9492738.

The previous prime is 18985451. The next prime is 18985513. The reversal of 18985478 is 87458981.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 87458981 = 2713 ⋅32237.

It is an alternating number because its digits alternate between odd and even.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4746368 + ... + 4746371.

It is an arithmetic number, because the mean of its divisors is an integer number (7119555).

Almost surely, 2^18985478 is an apocalyptic number.

18985478 is a deficient number, since it is larger than the sum of its proper divisors (9492742).

18985478 is an equidigital number, since it uses as much as digits as its factorization.

18985478 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9492741.

The product of its digits is 645120, while the sum is 50.

The square root of 18985478 is about 4357.2328374784. The cubic root of 18985478 is about 266.7721641608.

The spelling of 18985478 in words is "eighteen million, nine hundred eighty-five thousand, four hundred seventy-eight".