28812820 has 12 divisors (see below), whose sum is σ = 60506964. Its totient is φ = 11525120.

The previous prime is 28812799. The next prime is 28812821. The reversal of 28812820 is 2821882.

It can be written as a sum of positive squares in 2 ways, for example, as 4822416 + 23990404 = 2196^2 + 4898^2 .

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28812821) 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 3 ways as a sum of consecutive naturals, for example, 720301 + ... + 720340.

It is an arithmetic number, because the mean of its divisors is an integer number (5042247).

Almost surely, 2^28812820 is an apocalyptic number.

28812820 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

28812820 is an abundant number, since it is smaller than the sum of its proper divisors (31694144).

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

28812820 is a wasteful number, since it uses less digits than its factorization.

28812820 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1440650 (or 1440648 counting only the distinct ones).

The product of its (nonzero) digits is 4096, while the sum is 31.

The square root of 28812820 is about 5367.7574460849. The cubic root of 28812820 is about 306.5692480944.

The spelling of 28812820 in words is "twenty-eight million, eight hundred twelve thousand, eight hundred twenty".