28515840 has 160 divisors (see below), whose sum is σ = 94279680. Its totient is φ = 7348224.

The previous prime is 28515829. The next prime is 28515841. The reversal of 28515840 is 4851582.

It is a tau number, because it is divible by the number of its divisors (160).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28515841) 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, 360921 + ... + 360999.

It is an arithmetic number, because the mean of its divisors is an integer number (589248).

Almost surely, 2^28515840 is an apocalyptic number.

28515840 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 28515840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (47139840).

28515840 is an abundant number, since it is smaller than the sum of its proper divisors (65763840).

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

28515840 is an equidigital number, since it uses as much as digits as its factorization.

28515840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 152 (or 136 counting only the distinct ones).

The product of its (nonzero) digits is 12800, while the sum is 33.

The square root of 28515840 is about 5340.0224718628. The cubic root of 28515840 is about 305.5123164282.

The spelling of 28515840 in words is "twenty-eight million, five hundred fifteen thousand, eight hundred forty".