18685428 has 12 divisors (see below), whose sum is σ = 43599360. Its totient is φ = 6228472.

The previous prime is 18685423. The next prime is 18685439. The reversal of 18685428 is 82458681.

It is a tau number, because it is divible by the number of its divisors (12).

It is a self number, because there is not a number n which added to its sum of digits gives 18685428.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18685423) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 778548 + ... + 778571.

It is an arithmetic number, because the mean of its divisors is an integer number (3633280).

Almost surely, 2^18685428 is an apocalyptic number.

It is an amenable number.

18685428 is an abundant number, since it is smaller than the sum of its proper divisors (24913932).

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

18685428 is a wasteful number, since it uses less digits than its factorization.

18685428 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1557126 (or 1557124 counting only the distinct ones).

The product of its digits is 122880, while the sum is 42.

The square root of 18685428 is about 4322.6644560965. The cubic root of 18685428 is about 265.3593226958.

The spelling of 18685428 in words is "eighteen million, six hundred eighty-five thousand, four hundred twenty-eight".