28172717 has 4 divisors (see below), whose sum is σ = 29144220. Its totient is φ = 27201216.

The previous prime is 28172681. The next prime is 28172719. The reversal of 28172717 is 71727182.

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 22762441 + 5410276 = 4771^2 + 2326^2 .

It is a cyclic number.

It is not a de Polignac number, because 28172717 - 2⁸ = 28172461 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 (28172719) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 485708 + ... + 485765.

It is an arithmetic number, because the mean of its divisors is an integer number (7286055).

Almost surely, 2^28172717 is an apocalyptic number.

It is an amenable number.

28172717 is a deficient number, since it is larger than the sum of its proper divisors (971503).

28172717 is an equidigital number, since it uses as much as digits as its factorization.

28172717 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 971502.

The product of its digits is 10976, while the sum is 35.

The square root of 28172717 is about 5307.7977542480. The cubic root of 28172717 is about 304.2819874558.

Adding to 28172717 its reverse (71727182), we get a palindrome (99899899).

The spelling of 28172717 in words is "twenty-eight million, one hundred seventy-two thousand, seven hundred seventeen".