28681812 has 72 divisors (see below), whose sum is σ = 76134240. Its totient is φ = 9092160.

The previous prime is 28681801. The next prime is 28681813. The reversal of 28681812 is 21818682.

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 (28681813) 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 23 ways as a sum of consecutive naturals, for example, 86487 + ... + 86817.

It is an arithmetic number, because the mean of its divisors is an integer number (1057420).

Almost surely, 2^28681812 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 28681812, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (38067120).

28681812 is an abundant number, since it is smaller than the sum of its proper divisors (47452428).

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

28681812 is a wasteful number, since it uses less digits than its factorization.

28681812 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 453 (or 448 counting only the distinct ones).

The product of its digits is 12288, while the sum is 36.

The square root of 28681812 is about 5355.5403088764. The cubic root of 28681812 is about 306.1038991024.

Adding to 28681812 its product of digits (12288), we get a triangular number (28694100 = T₇₅₇₅).

The spelling of 28681812 in words is "twenty-eight million, six hundred eighty-one thousand, eight hundred twelve".