28665505 has 12 divisors (see below), whose sum is σ = 37810836. Its totient is φ = 20847200.

The previous prime is 28665503. The next prime is 28665529. The reversal of 28665505 is 50556682.

It can be written as a sum of positive squares in 2 ways, for example, as 18974736 + 9690769 = 4356^2 + 3113^2 .

It is not a de Polignac number, because 28665505 - 2¹ = 28665503 is a prime.

It is a super-2 number, since 2×28665505² = 1643422353810050, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (28665503) 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 11 ways as a sum of consecutive naturals, for example, 23086 + ... + 24295.

It is an arithmetic number, because the mean of its divisors is an integer number (3150903).

Almost surely, 2^28665505 is an apocalyptic number.

It is an amenable number.

28665505 is a deficient number, since it is larger than the sum of its proper divisors (9145331).

28665505 is a wasteful number, since it uses less digits than its factorization.

28665505 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 47408 (or 47397 counting only the distinct ones).

The product of its (nonzero) digits is 72000, while the sum is 37.

The square root of 28665505 is about 5354.0176503258. The cubic root of 28665505 is about 306.0458764714.

The spelling of 28665505 in words is "twenty-eight million, six hundred sixty-five thousand, five hundred five".