28289240 has 64 divisors (see below), whose sum is σ = 73820160. Its totient is φ = 9555840.

The previous prime is 28289237. The next prime is 28289249. The reversal of 28289240 is 4298282.

It is a Harshad number since it is a multiple of its sum of digits (35).

It is a self number, because there is not a number n which added to its sum of digits gives 28289240.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28289249) 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, 19169 + ... + 20591.

It is an arithmetic number, because the mean of its divisors is an integer number (1153440).

Almost surely, 2^28289240 is an apocalyptic number.

28289240 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 28289240, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (36910080).

28289240 is an abundant number, since it is smaller than the sum of its proper divisors (45530920).

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

28289240 is a wasteful number, since it uses less digits than its factorization.

28289240 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1512 (or 1508 counting only the distinct ones).

The product of its (nonzero) digits is 18432, while the sum is 35.

The square root of 28289240 is about 5318.7630140851. The cubic root of 28289240 is about 304.7009161658.

The spelling of 28289240 in words is "twenty-eight million, two hundred eighty-nine thousand, two hundred forty".