28240040 has 16 divisors (see below), whose sum is σ = 63540180. Its totient is φ = 11296000.

The previous prime is 28240027. The next prime is 28240049. The reversal of 28240040 is 4004282.

It can be written as a sum of positive squares in 2 ways, for example, as 28238596 + 1444 = 5314^2 + 38^2 .

It is a Harshad number since it is a multiple of its sum of digits (20).

It is a junction number, because it is equal to n+sod(n) for n = 28239994 and 28240021.

It is not an unprimeable number, because it can be changed into a prime (28240049) 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 3 ways as a sum of consecutive naturals, for example, 352961 + ... + 353040.

Almost surely, 2^28240040 is an apocalyptic number.

28240040 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

28240040 is an abundant number, since it is smaller than the sum of its proper divisors (35300140).

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

28240040 is a wasteful number, since it uses less digits than its factorization.

28240040 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 706012 (or 706008 counting only the distinct ones).

The product of its (nonzero) digits is 512, while the sum is 20.

The square root of 28240040 is about 5314.1358657829. The cubic root of 28240040 is about 304.5241707045.

The spelling of 28240040 in words is "twenty-eight million, two hundred forty thousand, forty".