28298440 has 32 divisors (see below), whose sum is σ = 64395000. Its totient is φ = 11190784.

The previous prime is 28298437. The next prime is 28298447. The reversal of 28298440 is 4489282.

It can be written as a sum of positive squares in 4 ways, for example, as 18198756 + 10099684 = 4266^2 + 3178^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 28298440.

It is not an unprimeable number, because it can be changed into a prime (28298447) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 415 + ... + 7534.

Almost surely, 2^28298440 is an apocalyptic number.

28298440 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 28298440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (32197500).

28298440 is an abundant number, since it is smaller than the sum of its proper divisors (36096560).

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

28298440 is a wasteful number, since it uses less digits than its factorization.

28298440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8049 (or 8045 counting only the distinct ones).

The product of its (nonzero) digits is 36864, while the sum is 37.

The square root of 28298440 is about 5319.6278065293. The cubic root of 28298440 is about 304.7339433827.

It can be divided in two parts, 282984 and 40, that added together give a square (283024 = 532²).

The spelling of 28298440 in words is "twenty-eight million, two hundred ninety-eight thousand, four hundred forty".