28499220 has 36 divisors (see below), whose sum is σ = 86448180. Its totient is φ = 7599744.

The previous prime is 28499209. The next prime is 28499227. The reversal of 28499220 is 2299482.

It can be written as a sum of positive squares in 2 ways, for example, as 19820304 + 8678916 = 4452^2 + 2946^2 .

It is a tau number, because it is divible by the number of its divisors (36).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28499227) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 78985 + ... + 79344.

Almost surely, 2^28499220 is an apocalyptic number.

28499220 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

28499220 is an abundant number, since it is smaller than the sum of its proper divisors (57948960).

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

28499220 is a wasteful number, since it uses less digits than its factorization.

28499220 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 158344 (or 158339 counting only the distinct ones).

The product of its (nonzero) digits is 20736, while the sum is 36.

The square root of 28499220 is about 5338.4660718225. The cubic root of 28499220 is about 305.4529505753.

The spelling of 28499220 in words is "twenty-eight million, four hundred ninety-nine thousand, two hundred twenty".