28920 has 32 divisors (see below), whose sum is σ = 87120. Its totient is φ = 7680.

The previous prime is 28909. The next prime is 28921. The reversal of 28920 is 2982.

28920 = T₇₁ + T₇₂ + ... + T₈₀.

28920 is nontrivially palindromic in base 14.

28920 is digitally balanced in base 6, because in such base it contains all the possibile digits an equal number of times.

28920 is a nontrivial binomial coefficient, being equal to C(241, 2).

It is a Smith number, since the sum of its digits (21) coincides with the sum of the digits of its prime factors.

28920 is strictly pandigital in base 6.

It is a nialpdrome in base 15.

It is a zygodrome in base 2.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28921) by changing a digit.

28920 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 7 ways as a sum of consecutive naturals, for example, 1 + ... + 240.

2²⁸⁹²⁰ is an apocalyptic number.

28920 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

28920 is the 240-th triangular number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 28920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (43560).

28920 is an abundant number, since it is smaller than the sum of its proper divisors (58200).

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

28920 is a wasteful number, since it uses less digits than its factorization.

28920 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 255 (or 251 counting only the distinct ones).

The product of its (nonzero) digits is 288, while the sum is 21.

The square root of 28920 is about 170.0588133559. The cubic root of 28920 is about 30.6948910497.

The spelling of 28920 in words is "twenty-eight thousand, nine hundred twenty".