18978628 has 6 divisors (see below), whose sum is σ = 33212606. Its totient is φ = 9489312.

The previous prime is 18978601. The next prime is 18978637. The reversal of 18978628 is 82687981.

It can be written as a sum of positive squares in only one way, i.e., 17994564 + 984064 = 4242^2 + 992^2 .

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2372325 + ... + 2372332.

Almost surely, 2^18978628 is an apocalyptic number.

It is an amenable number.

18978628 is a deficient number, since it is larger than the sum of its proper divisors (14233978).

18978628 is a wasteful number, since it uses less digits than its factorization.

18978628 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4744661 (or 4744659 counting only the distinct ones).

The product of its digits is 387072, while the sum is 49.

The square root of 18978628 is about 4356.4467172226. The cubic root of 18978628 is about 266.7400763173.

The spelling of 18978628 in words is "eighteen million, nine hundred seventy-eight thousand, six hundred twenty-eight".