28724560 has 40 divisors (see below), whose sum is σ = 70716456. Its totient is φ = 10813440.

The previous prime is 28724503. The next prime is 28724581. The reversal of 28724560 is 6542782.

It can be written as a sum of positive squares in 4 ways, for example, as 8904256 + 19820304 = 2984^2 + 4452^2 .

It is a tau number, because it is divible by the number of its divisors (40).

It is a Harshad number since it is a multiple of its sum of digits (34).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 9201 + ... + 11920.

Almost surely, 2^28724560 is an apocalyptic number.

28724560 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

28724560 is an abundant number, since it is smaller than the sum of its proper divisors (41991896).

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

28724560 is a wasteful number, since it uses less digits than its factorization.

28724560 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 21151 (or 21145 counting only the distinct ones).

The product of its (nonzero) digits is 26880, while the sum is 34.

The square root of 28724560 is about 5359.5298301250. The cubic root of 28724560 is about 306.2558982621.

The spelling of 28724560 in words is "twenty-eight million, seven hundred twenty-four thousand, five hundred sixty".