28185317 has 2 divisors, whose sum is σ = 28185318. Its totient is φ = 28185316.

The previous prime is 28185299. The next prime is 28185319. The reversal of 28185317 is 71358182.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 15124321 + 13060996 = 3889^2 + 3614^2 .

It is a cyclic number.

It is not a de Polignac number, because 28185317 - 2⁸ = 28185061 is a prime.

Together with 28185319, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (28185319) 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 as a sum of consecutive naturals, namely, 14092658 + 14092659.

It is an arithmetic number, because the mean of its divisors is an integer number (14092659).

Almost surely, 2^28185317 is an apocalyptic number.

It is an amenable number.

28185317 is a deficient number, since it is larger than the sum of its proper divisors (1).

28185317 is an equidigital number, since it uses as much as digits as its factorization.

28185317 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 13440, while the sum is 35.

The square root of 28185317 is about 5308.9845545076. The cubic root of 28185317 is about 304.3273431761.

The spelling of 28185317 in words is "twenty-eight million, one hundred eighty-five thousand, three hundred seventeen".