28785917 has 2 divisors, whose sum is σ = 28785918. Its totient is φ = 28785916.

The previous prime is 28785899. The next prime is 28785929. The reversal of 28785917 is 71958782.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 17422276 + 11363641 = 4174^2 + 3371^2 .

It is a cyclic number.

It is not a de Polignac number, because 28785917 - 2⁶ = 28785853 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (28785517) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 14392958 + 14392959.

It is an arithmetic number, because the mean of its divisors is an integer number (14392959).

Almost surely, 2^28785917 is an apocalyptic number.

It is an amenable number.

28785917 is a deficient number, since it is larger than the sum of its proper divisors (1).

28785917 is an equidigital number, since it uses as much as digits as its factorization.

28785917 is an evil number, because the sum of its binary digits is even.

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

The square root of 28785917 is about 5365.2508795023. The cubic root of 28785917 is about 306.4738021460.

The spelling of 28785917 in words is "twenty-eight million, seven hundred eighty-five thousand, nine hundred seventeen".