28012320 has 216 divisors, whose sum is σ = 111479004. Its totient is φ = 6386688.

The previous prime is 28012319. The next prime is 28012337. The reversal of 28012320 is 2321082.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 28005264 + 7056 = 5292^2 + 84^2 .

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a junction number, because it is equal to n+sod(n) for n = 28012293 and 28012302.

It is an unprimeable number.

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 35 ways as a sum of consecutive naturals, for example, 70362 + ... + 70758.

Almost surely, 2^28012320 is an apocalyptic number.

28012320 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 28012320, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (55739502).

28012320 is an abundant number, since it is smaller than the sum of its proper divisors (83466684).

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

28012320 is a wasteful number, since it uses less digits than its factorization.

28012320 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 432 (or 414 counting only the distinct ones).

The product of its (nonzero) digits is 192, while the sum is 18.

The square root of 28012320 is about 5292.6666246799. Note that the first 4 decimals coincide. The cubic root of 28012320 is about 303.7034272954.

The spelling of 28012320 in words is "twenty-eight million, twelve thousand, three hundred twenty".