28308820 has 12 divisors (see below), whose sum is σ = 59448564. Its totient is φ = 11323520.

The previous prime is 28308793. The next prime is 28308821. The reversal of 28308820 is 2880382.

It can be written as a sum of positive squares in 2 ways, for example, as 8363664 + 19945156 = 2892^2 + 4466^2 .

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28308821) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 707701 + ... + 707740.

It is an arithmetic number, because the mean of its divisors is an integer number (4954047).

Almost surely, 2^28308820 is an apocalyptic number.

28308820 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

28308820 is an abundant number, since it is smaller than the sum of its proper divisors (31139744).

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

28308820 is a wasteful number, since it uses less digits than its factorization.

28308820 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1415450 (or 1415448 counting only the distinct ones).

The product of its (nonzero) digits is 6144, while the sum is 31.

The square root of 28308820 is about 5320.6033492453. The cubic root of 28308820 is about 304.7711981061.

The spelling of 28308820 in words is "twenty-eight million, three hundred eight thousand, eight hundred twenty".