28724720 has 40 divisors (see below), whose sum is σ = 67239744. Its totient is φ = 11411712.

The previous prime is 28724719. The next prime is 28724737. The reversal of 28724720 is 2742782.

It is a happy number.

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

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, 11417 + ... + 13703.

Almost surely, 2^28724720 is an apocalyptic number.

28724720 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 28724720, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (33619872).

28724720 is an abundant number, since it is smaller than the sum of its proper divisors (38515024).

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

28724720 is a wasteful number, since it uses less digits than its factorization.

28724720 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2457 (or 2451 counting only the distinct ones).

The product of its (nonzero) digits is 12544, while the sum is 32.

The square root of 28724720 is about 5359.5447567867. The cubic root of 28724720 is about 306.2564668911.

The spelling of 28724720 in words is "twenty-eight million, seven hundred twenty-four thousand, seven hundred twenty".