28648665 has 36 divisors (see below), whose sum is σ = 51497004. Its totient is φ = 14732928.

The previous prime is 28648657. The next prime is 28648699. The reversal of 28648665 is 56684682.

28648665 is a nontrivial binomial coefficient, being equal to C(7570, 2).

It can be written as a sum of positive squares in 6 ways, for example, as 4761 + 28643904 = 69^2 + 5352^2 .

It is not a de Polignac number, because 28648665 - 2³ = 28648657 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a self number, because there is not a number n which added to its sum of digits gives 28648665.

It is an unprimeable number.

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 35 ways as a sum of consecutive naturals, for example, 37467 + ... + 38223.

Almost surely, 2^28648665 is an apocalyptic number.

28648665 is the 7569-th triangular number and also the 3785-th hexagonal number.

It is an amenable number.

28648665 is a deficient number, since it is larger than the sum of its proper divisors (22848339).

28648665 is a wasteful number, since it uses less digits than its factorization.

28648665 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 826 (or 794 counting only the distinct ones).

The product of its digits is 552960, while the sum is 45.

The square root of 28648665 is about 5352.4447685147. Note that the first 3 decimals coincide. The cubic root of 28648665 is about 305.9859342503.

The spelling of 28648665 in words is "twenty-eight million, six hundred forty-eight thousand, six hundred sixty-five".