28520640 has 112 divisors (see below), whose sum is σ = 100644960. Its totient is φ = 7603200.

The previous prime is 28520633. The next prime is 28520641. The reversal of 28520640 is 4602582.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28520641) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 6990 + ... + 10290.

Almost surely, 2^28520640 is an apocalyptic number.

28520640 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 28520640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (50322480).

28520640 is an abundant number, since it is smaller than the sum of its proper divisors (72124320).

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

28520640 is a wasteful number, since it uses less digits than its factorization.

28520640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3327 (or 3311 counting only the distinct ones).

The product of its (nonzero) digits is 3840, while the sum is 27.

The square root of 28520640 is about 5340.4718892622. The cubic root of 28520640 is about 305.5294575077.

The spelling of 28520640 in words is "twenty-eight million, five hundred twenty thousand, six hundred forty".