28171717 has 6 divisors (see below), whose sum is σ = 32771238. Its totient is φ = 24147144.

The previous prime is 28171697. The next prime is 28171729. The reversal of 28171717 is 71717182.

It can be written as a sum of positive squares in only one way, i.e., 24910081 + 3261636 = 4991^2 + 1806^2 .

It is not a de Polignac number, because 28171717 - 2⁷ = 28171589 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28171747) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 287418 + ... + 287515.

It is an arithmetic number, because the mean of its divisors is an integer number (5461873).

Almost surely, 2^28171717 is an apocalyptic number.

It is an amenable number.

28171717 is a deficient number, since it is larger than the sum of its proper divisors (4599521).

28171717 is an equidigital number, since it uses as much as digits as its factorization.

28171717 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 574947 (or 574940 counting only the distinct ones).

The product of its digits is 5488, while the sum is 34.

The square root of 28171717 is about 5307.7035523850. The cubic root of 28171717 is about 304.2783872163.

Adding to 28171717 its reverse (71717182), we get a palindrome (99888899).

The spelling of 28171717 in words is "twenty-eight million, one hundred seventy-one thousand, seven hundred seventeen".