28365640 has 16 divisors (see below), whose sum is σ = 63822780. Its totient is φ = 11346240.

The previous prime is 28365619. The next prime is 28365641. The reversal of 28365640 is 4656382.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 27815076 + 550564 = 5274^2 + 742^2 .

It is a junction number, because it is equal to n+sod(n) for n = 28365596 and 28365605.

It is not an unprimeable number, because it can be changed into a prime (28365641) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 354531 + ... + 354610.

Almost surely, 2^28365640 is an apocalyptic number.

28365640 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

28365640 is an abundant number, since it is smaller than the sum of its proper divisors (35457140).

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

28365640 is a wasteful number, since it uses less digits than its factorization.

28365640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 709152 (or 709148 counting only the distinct ones).

The product of its (nonzero) digits is 34560, while the sum is 34.

The square root of 28365640 is about 5325.9402925681. The cubic root of 28365640 is about 304.9749688317.

The spelling of 28365640 in words is "twenty-eight million, three hundred sixty-five thousand, six hundred forty".