28684840 has 32 divisors (see below), whose sum is σ = 65215080. Its totient is φ = 11354112.

The previous prime is 28684837. The next prime is 28684847. The reversal of 28684840 is 4848682.

It can be written as a sum of positive squares in 4 ways, for example, as 17489124 + 11195716 = 4182^2 + 3346^2 .

It is a Harshad number since it is a multiple of its sum of digits (40).

It is a junction number, because it is equal to n+sod(n) for n = 28684793 and 28684802.

It is not an unprimeable number, because it can be changed into a prime (28684847) 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, 184 + ... + 7576.

Almost surely, 2^28684840 is an apocalyptic number.

28684840 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

28684840 is an abundant number, since it is smaller than the sum of its proper divisors (36530240).

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

28684840 is a wasteful number, since it uses less digits than its factorization.

28684840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7501 (or 7497 counting only the distinct ones).

The product of its (nonzero) digits is 98304, while the sum is 40.

The square root of 28684840 is about 5355.8229993158. The cubic root of 28684840 is about 306.1146707369.

The spelling of 28684840 in words is "twenty-eight million, six hundred eighty-four thousand, eight hundred forty".