18978428 has 24 divisors (see below), whose sum is σ = 38220000. Its totient is φ = 8077248.

The previous prime is 18978419. The next prime is 18978439. The reversal of 18978428 is 82487981.

It is a Smith number, since the sum of its digits (47) coincides with the sum of the digits of its prime factors.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1898 + ... + 6446.

It is an arithmetic number, because the mean of its divisors is an integer number (1592500).

Almost surely, 2^18978428 is an apocalyptic number.

It is an amenable number.

18978428 is an abundant number, since it is smaller than the sum of its proper divisors (19241572).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

18978428 is a wasteful number, since it uses less digits than its factorization.

18978428 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4709 (or 4707 counting only the distinct ones).

The product of its digits is 258048, while the sum is 47.

The square root of 18978428 is about 4356.4237626751. The cubic root of 18978428 is about 266.7391393299.

The spelling of 18978428 in words is "eighteen million, nine hundred seventy-eight thousand, four hundred twenty-eight".