28521240 has 256 divisors, whose sum is σ = 104509440. Its totient is φ = 6144000.

The previous prime is 28521217. The next prime is 28521247. The reversal of 28521240 is 4212582.

It is a super-2 number, since 2×28521240² = 1626922262275200, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (24).

It is a self number, because there is not a number n which added to its sum of digits gives 28521240.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28521247) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 695620 + ... + 695660.

It is an arithmetic number, because the mean of its divisors is an integer number (408240).

Almost surely, 2^28521240 is an apocalyptic number.

28521240 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 28521240, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (52254720).

28521240 is an abundant number, since it is smaller than the sum of its proper divisors (75988200).

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

28521240 is a wasteful number, since it uses less digits than its factorization.

28521240 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 114 (or 110 counting only the distinct ones).

The product of its (nonzero) digits is 1280, while the sum is 24.

The square root of 28521240 is about 5340.5280637780. The cubic root of 28521240 is about 305.5316000075.

The spelling of 28521240 in words is "twenty-eight million, five hundred twenty-one thousand, two hundred forty".