28512720 has 90 divisors (see below), whose sum is σ = 96238818. Its totient is φ = 7565184.

The previous prime is 28512719. The next prime is 28512739. The reversal of 28512720 is 2721582.

It can be written as a sum of positive squares in only one way, i.e., 22810176 + 5702544 = 4776^2 + 2388^2 .

It is a tau number, because it is divible by the number of its divisors (90).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 143181 + ... + 143379.

Almost surely, 2^28512720 is an apocalyptic number.

28512720 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 28512720, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (48119409).

28512720 is an abundant number, since it is smaller than the sum of its proper divisors (67726098).

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

28512720 is a wasteful number, since it uses less digits than its factorization.

28512720 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 417 (or 209 counting only the distinct ones).

The product of its (nonzero) digits is 2240, while the sum is 27.

The square root of 28512720 is about 5339.7303302695. The cubic root of 28512720 is about 305.5011736950.

The spelling of 28512720 in words is "twenty-eight million, five hundred twelve thousand, seven hundred twenty".