28644720 has 80 divisors (see below), whose sum is σ = 95639712. Its totient is φ = 7050240.

The previous prime is 28644719. The next prime is 28644731. The reversal of 28644720 is 2744682.

It is a tau number, because it is divible by the number of its divisors (80).

It is a hoax number, since the sum of its digits (33) coincides with the sum of the digits of its distinct prime factors.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1471 + ... + 7710.

Almost surely, 2^28644720 is an apocalyptic number.

28644720 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 28644720, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (47819856).

28644720 is an abundant number, since it is smaller than the sum of its proper divisors (66994992).

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

28644720 is a wasteful number, since it uses less digits than its factorization.

28644720 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9210 (or 9204 counting only the distinct ones).

The product of its (nonzero) digits is 21504, while the sum is 33.

The square root of 28644720 is about 5352.0762326409. The cubic root of 28644720 is about 305.9718885705.

The spelling of 28644720 in words is "twenty-eight million, six hundred forty-four thousand, seven hundred twenty".