28840720 has 20 divisors (see below), whose sum is σ = 67054860. Its totient is φ = 11536256.

The previous prime is 28840699. The next prime is 28840769. The reversal of 28840720 is 2704882.

It can be written as a sum of positive squares in 2 ways, for example, as 6411024 + 22429696 = 2532^2 + 4736^2 .

It is a tau number, because it is divible by the number of its divisors (20).

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 180175 + ... + 180334.

It is an arithmetic number, because the mean of its divisors is an integer number (3352743).

Almost surely, 2^28840720 is an apocalyptic number.

28840720 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

28840720 is an abundant number, since it is smaller than the sum of its proper divisors (38214140).

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

28840720 is a wasteful number, since it uses less digits than its factorization.

28840720 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 360522 (or 360516 counting only the distinct ones).

The product of its (nonzero) digits is 7168, while the sum is 31.

The square root of 28840720 is about 5370.3556679237. The cubic root of 28840720 is about 306.6681684447.

The spelling of 28840720 in words is "twenty-eight million, eight hundred forty thousand, seven hundred twenty".