28515240 has 160 divisors (see below), whose sum is σ = 103367880. Its totient is φ = 7008768.

The previous prime is 28515217. The next prime is 28515247. The reversal of 28515240 is 4251582.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 25948836 + 2566404 = 5094^2 + 1602^2 .

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 (28515247) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 41782 + ... + 42458.

Almost surely, 2^28515240 is an apocalyptic number.

28515240 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 28515240, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (51683940).

28515240 is an abundant number, since it is smaller than the sum of its proper divisors (74852640).

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

28515240 is a wasteful number, since it uses less digits than its factorization.

28515240 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 713 (or 700 counting only the distinct ones).

The product of its (nonzero) digits is 3200, while the sum is 27.

The square root of 28515240 is about 5339.9662920284. The cubic root of 28515240 is about 305.5101736580.

The spelling of 28515240 in words is "twenty-eight million, five hundred fifteen thousand, two hundred forty".