28816640 has 72 divisors (see below), whose sum is σ = 70640640. Its totient is φ = 11257856.

The previous prime is 28816609. The next prime is 28816643. The reversal of 28816640 is 4661882.

It is a self number, because there is not a number n which added to its sum of digits gives 28816640.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28816643) 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, 59921 + ... + 60399.

It is an arithmetic number, because the mean of its divisors is an integer number (981120).

Almost surely, 2^28816640 is an apocalyptic number.

28816640 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 28816640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (35320320).

28816640 is an abundant number, since it is smaller than the sum of its proper divisors (41824000).

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

28816640 is an equidigital number, since it uses as much as digits as its factorization.

28816640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 547 (or 533 counting only the distinct ones).

The product of its (nonzero) digits is 18432, while the sum is 35.

The square root of 28816640 is about 5368.1132625905. The cubic root of 28816640 is about 306.5827957996.

The spelling of 28816640 in words is "twenty-eight million, eight hundred sixteen thousand, six hundred forty".