28204220 has 24 divisors (see below), whose sum is σ = 64613808. Its totient is φ = 10256000.

The previous prime is 28204219. The next prime is 28204223. The reversal of 28204220 is 2240282.

It is a Harshad number since it is a multiple of its sum of digits (20).

It is a junction number, because it is equal to n+sod(n) for n = 28204192 and 28204201.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28204223) 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, 63881 + ... + 64320.

It is an arithmetic number, because the mean of its divisors is an integer number (2692242).

Almost surely, 2^28204220 is an apocalyptic number.

28204220 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

28204220 is an abundant number, since it is smaller than the sum of its proper divisors (36409588).

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

28204220 is a wasteful number, since it uses less digits than its factorization.

28204220 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 128221 (or 128219 counting only the distinct ones).

The product of its (nonzero) digits is 512, while the sum is 20.

The square root of 28204220 is about 5310.7645400639. The cubic root of 28204220 is about 304.3953622111.

The spelling of 28204220 in words is "twenty-eight million, two hundred four thousand, two hundred twenty".