28717985 has 4 divisors (see below), whose sum is σ = 34461588. Its totient is φ = 22974384.

The previous prime is 28717973. The next prime is 28717993. The reversal of 28717985 is 58971782.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 7447441 + 21270544 = 2729^2 + 4612^2 .

It is a cyclic number.

It is not a de Polignac number, because 28717985 - 2⁶ = 28717921 is a prime.

It is a Duffinian number.

It is a Curzon number.

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 3 ways as a sum of consecutive naturals, for example, 2871794 + ... + 2871803.

It is an arithmetic number, because the mean of its divisors is an integer number (8615397).

Almost surely, 2^28717985 is an apocalyptic number.

It is an amenable number.

28717985 is a deficient number, since it is larger than the sum of its proper divisors (5743603).

28717985 is an equidigital number, since it uses as much as digits as its factorization.

28717985 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5743602.

The product of its digits is 282240, while the sum is 47.

The square root of 28717985 is about 5358.9164016618. The cubic root of 28717985 is about 306.2325293380.

The spelling of 28717985 in words is "twenty-eight million, seven hundred seventeen thousand, nine hundred eighty-five".