28722816 has 64 divisors (see below), whose sum is σ = 84782400. Its totient is φ = 9573120.

The previous prime is 28722803. The next prime is 28722817. The reversal of 28722816 is 61822782.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (64).

It is a Smith number, since the sum of its digits (36) coincides with the sum of the digits of its prime factors.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a nialpdrome in base 12.

It is not an unprimeable number, because it can be changed into a prime (28722817) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 700 + ... + 7611.

It is an arithmetic number, because the mean of its divisors is an integer number (1324725).

Almost surely, 2^28722816 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 28722816, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (42391200).

28722816 is an abundant number, since it is smaller than the sum of its proper divisors (56059584).

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

28722816 is an equidigital number, since it uses as much as digits as its factorization.

28722816 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8334 (or 8316 counting only the distinct ones).

The product of its digits is 21504, while the sum is 36.

The square root of 28722816 is about 5359.3671268164. The cubic root of 28722816 is about 306.2497000691.

The spelling of 28722816 in words is "twenty-eight million, seven hundred twenty-two thousand, eight hundred sixteen".