28521920 has 168 divisors, whose sum is σ = 84435696. Its totient is φ = 9117696.

The previous prime is 28521901. The next prime is 28521929. The reversal of 28521920 is 2912582.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28521929) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 266507 + ... + 266613.

Almost surely, 2^28521920 is an apocalyptic number.

28521920 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 28521920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (42217848).

28521920 is an abundant number, since it is smaller than the sum of its proper divisors (55913776).

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

28521920 is a wasteful number, since it uses less digits than its factorization.

28521920 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 155 (or 138 counting only the distinct ones).

The product of its (nonzero) digits is 2880, while the sum is 29.

The square root of 28521920 is about 5340.5917275148. The cubic root of 28521920 is about 305.5340281375.

The spelling of 28521920 in words is "twenty-eight million, five hundred twenty-one thousand, nine hundred twenty".