28780 has 12 divisors (see below), whose sum is σ = 60480. Its totient is φ = 11504.

The previous prime is 28771. The next prime is 28789. The reversal of 28780 is 8782.

It is an interprime number because it is at equal distance from previous prime (28771) and next prime (28789).

It is not an unprimeable number, because it can be changed into a prime (28789) by changing a digit.

28780 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 700 + ... + 739.

It is an arithmetic number, because the mean of its divisors is an integer number (5040).

2²⁸⁷⁸⁰ is an apocalyptic number.

28780 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

28780 is an abundant number, since it is smaller than the sum of its proper divisors (31700).

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

It is a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (30240).

28780 is a wasteful number, since it uses less digits than its factorization.

28780 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1448 (or 1446 counting only the distinct ones).

The product of its (nonzero) digits is 896, while the sum is 25.

The square root of 28780 is about 169.6466916860. The cubic root of 28780 is about 30.6452801949.

It can be divided in two parts, 28 and 780, that added together give a palindrome (808).

The spelling of 28780 in words is "twenty-eight thousand, seven hundred eighty".