128784 has 20 divisors (see below), whose sum is σ = 332816. Its totient is φ = 42912.

The previous prime is 128767. The next prime is 128813. The reversal of 128784 is 487821.

Added to its reverse (487821) it gives a triangular number (616605 = T₁₁₁₀).

It is a super-3 number, since 3×128784³ = 6407771033382912, which contains 333 as substring.

It is a Smith number, since the sum of its digits (30) coincides with the sum of the digits of its prime factors.

It is an unprimeable number.

128784 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1294 + ... + 1389.

2¹²⁸⁷⁸⁴ is an apocalyptic number.

It is an amenable number.

128784 is an abundant number, since it is smaller than the sum of its proper divisors (204032).

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

128784 is a wasteful number, since it uses less digits than its factorization.

128784 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2694 (or 2688 counting only the distinct ones).

The product of its digits is 3584, while the sum is 30.

The square root of 128784 is about 358.8648770777. The cubic root of 128784 is about 50.4995261858.

Adding to 128784 its reverse (487821), we get a triangular number (616605 = T₁₁₁₀).

The spelling of 128784 in words is "one hundred twenty-eight thousand, seven hundred eighty-four".