28100220 has 48 divisors (see below), whose sum is σ = 79476768. Its totient is φ = 7417600.

The previous prime is 28100213. The next prime is 28100243. The reversal of 28100220 is 2200182.

It is a Harshad number since it is a multiple of its sum of digits (15).

It is a self number, because there is not a number n which added to its sum of digits gives 28100220.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 3742 + ... + 8378.

It is an arithmetic number, because the mean of its divisors is an integer number (1655766).

Almost surely, 2^28100220 is an apocalyptic number.

28100220 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 28100220, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (39738384).

28100220 is an abundant number, since it is smaller than the sum of its proper divisors (51376548).

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

28100220 is a wasteful number, since it uses less digits than its factorization.

28100220 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4750 (or 4748 counting only the distinct ones).

The product of its (nonzero) digits is 64, while the sum is 15.

The square root of 28100220 is about 5300.9640632625. The cubic root of 28100220 is about 304.0207597781.

The spelling of 28100220 in words is "twenty-eight million, one hundred thousand, two hundred twenty".