28666565 has 8 divisors (see below), whose sum is σ = 34651800. Its totient is φ = 22765312.

The previous prime is 28666559. The next prime is 28666571. The reversal of 28666565 is 56566682.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (28666559) and next prime (28666571).

It can be written as a sum of positive squares in 4 ways, for example, as 7745089 + 20921476 = 2783^2 + 4574^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 28666565 - 2⁶ = 28666501 is a prime.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 20240 + ... + 21609.

It is an arithmetic number, because the mean of its divisors is an integer number (4331475).

Almost surely, 2^28666565 is an apocalyptic number.

It is an amenable number.

28666565 is a deficient number, since it is larger than the sum of its proper divisors (5985235).

28666565 is a wasteful number, since it uses less digits than its factorization.

28666565 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 41991.

The product of its digits is 518400, while the sum is 44.

The square root of 28666565 is about 5354.1166404926. The cubic root of 28666565 is about 306.0496487712.

The spelling of 28666565 in words is "twenty-eight million, six hundred sixty-six thousand, five hundred sixty-five".