28281312 has 72 divisors (see below), whose sum is σ = 83426616. Its totient is φ = 9424512.

The previous prime is 28281311. The next prime is 28281343. The reversal of 28281312 is 21318282.

It is a tau number, because it is divible by the number of its divisors (72).

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a nude number because it is divisible by every one of its digits.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28281311) 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, 5958 + ... + 9594.

It is an arithmetic number, because the mean of its divisors is an integer number (1158703).

Almost surely, 2^28281312 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 28281312, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (41713308).

28281312 is an abundant number, since it is smaller than the sum of its proper divisors (55145304).

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

28281312 is an equidigital number, since it uses as much as digits as its factorization.

28281312 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3662 (or 3642 counting only the distinct ones).

The product of its digits is 1536, while the sum is 27.

The square root of 28281312 is about 5318.0176757886. The cubic root of 28281312 is about 304.6724495761.

Adding to 28281312 its reverse (21318282), we get a palindrome (49599594).

The spelling of 28281312 in words is "twenty-eight million, two hundred eighty-one thousand, three hundred twelve".