28220 has 24 divisors (see below), whose sum is σ = 63504. Its totient is φ = 10496.

The previous prime is 28219. The next prime is 28229. The reversal of 28220 is 2282.

28220 = T₃₆ + T₃₇ + ... + T₅₉.

28220 is an undulating number in base 13.

It is a junction number, because it is equal to n+sod(n) for n = 28195 and 28204.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28229) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 299 + ... + 381.

It is an arithmetic number, because the mean of its divisors is an integer number (2646).

2²⁸²²⁰ is an apocalyptic number.

28220 is a gapful number since it is divisible by the number (20) 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 28220, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (31752).

28220 is an abundant number, since it is smaller than the sum of its proper divisors (35284).

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

28220 is a wasteful number, since it uses less digits than its factorization.

28220 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 109 (or 107 counting only the distinct ones).

The product of its (nonzero) digits is 64, while the sum is 14.

The square root of 28220 is about 167.9880948163. The cubic root of 28220 is about 30.4452120423.

The spelling of 28220 in words is "twenty-eight thousand, two hundred twenty".