28538220 has 24 divisors (see below), whose sum is σ = 79907184. Its totient is φ = 7610176.

The previous prime is 28538183. The next prime is 28538227. The reversal of 28538220 is 2283582.

It is a Harshad number since it is a multiple of its sum of digits (30).

It is not an unprimeable number, because it can be changed into a prime (28538227) 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, 237759 + ... + 237878.

It is an arithmetic number, because the mean of its divisors is an integer number (3329466).

Almost surely, 2^28538220 is an apocalyptic number.

28538220 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

28538220 is an abundant number, since it is smaller than the sum of its proper divisors (51368964).

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

28538220 is a wasteful number, since it uses less digits than its factorization.

28538220 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 475649 (or 475647 counting only the distinct ones).

The product of its (nonzero) digits is 7680, while the sum is 30.

The square root of 28538220 is about 5342.1175576732. The cubic root of 28538220 is about 305.5922202957.

The spelling of 28538220 in words is "twenty-eight million, five hundred thirty-eight thousand, two hundred twenty".