28122820 has 36 divisors (see below), whose sum is σ = 64920492. Its totient is φ = 10225600.

The previous prime is 28122799. The next prime is 28122821. The reversal of 28122820 is 2822182.

It can be written as a sum of positive squares in 2 ways, for example, as 5541316 + 22581504 = 2354^2 + 4752^2 .

It is not an unprimeable number, because it can be changed into a prime (28122821) 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, 3391 + ... + 8230.

It is an arithmetic number, because the mean of its divisors is an integer number (1803347).

Almost surely, 2^28122820 is an apocalyptic number.

28122820 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

28122820 is an abundant number, since it is smaller than the sum of its proper divisors (36797672).

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

28122820 is a wasteful number, since it uses less digits than its factorization.

28122820 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11652 (or 11639 counting only the distinct ones).

The product of its (nonzero) digits is 1024, while the sum is 25.

The square root of 28122820 is about 5303.0953225451. The cubic root of 28122820 is about 304.1022422717.

The spelling of 28122820 in words is "twenty-eight million, one hundred twenty-two thousand, eight hundred twenty".