18787428 has 108 divisors (see below), whose sum is σ = 55189680. Its totient is φ = 5369760.

The previous prime is 18787423. The next prime is 18787441. The reversal of 18787428 is 82478781.

It is not an unprimeable number, because it can be changed into a prime (18787423) by changing a digit.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 82651 + ... + 82877.

Almost surely, 2^18787428 is an apocalyptic number.

18787428 is a gapful number since it is divisible by the number (18) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 18787428, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (27594840).

18787428 is an abundant number, since it is smaller than the sum of its proper divisors (36402252).

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

18787428 is a wasteful number, since it uses less digits than its factorization.

18787428 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 278 (or 262 counting only the distinct ones).

The product of its digits is 200704, while the sum is 45.

The square root of 18787428 is about 4334.4466774895. The cubic root of 18787428 is about 265.8412945165.

The spelling of 18787428 in words is "eighteen million, seven hundred eighty-seven thousand, four hundred twenty-eight".