28720584 has 48 divisors (see below), whose sum is σ = 79894620. Its totient is φ = 9313920.

The previous prime is 28720577. The next prime is 28720613. The reversal of 28720584 is 48502782.

It is a happy number.

28720584 is a `hidden beast` number, since 2 + 8 + 72 + 0 + 584 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 28323684 + 396900 = 5322^2 + 630^2 .

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

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 2727 + ... + 8054.

Almost surely, 2^28720584 is an apocalyptic number.

28720584 is a gapful number since it is divisible by the number (24) formed by its first and last digit.

It is an amenable number.

28720584 is an abundant number, since it is smaller than the sum of its proper divisors (51174036).

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

28720584 is a wasteful number, since it uses less digits than its factorization.

28720584 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10830 (or 10823 counting only the distinct ones).

The product of its (nonzero) digits is 35840, while the sum is 36.

The square root of 28720584 is about 5359.1588892288. The cubic root of 28720584 is about 306.2417671534.

The spelling of 28720584 in words is "twenty-eight million, seven hundred twenty thousand, five hundred eighty-four".