28239817 has 2 divisors, whose sum is σ = 28239818. Its totient is φ = 28239816.

The previous prime is 28239803. The next prime is 28239851. The reversal of 28239817 is 71893282.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 22838841 + 5400976 = 4779^2 + 2324^2 .

It is a cyclic number.

It is not a de Polignac number, because 28239817 - 2⁷ = 28239689 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 28239817.

It is not a weakly prime, because it can be changed into another prime (28239877) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 14119908 + 14119909.

It is an arithmetic number, because the mean of its divisors is an integer number (14119909).

Almost surely, 2^28239817 is an apocalyptic number.

It is an amenable number.

28239817 is a deficient number, since it is larger than the sum of its proper divisors (1).

28239817 is an equidigital number, since it uses as much as digits as its factorization.

28239817 is an evil number, because the sum of its binary digits is even.

The product of its digits is 48384, while the sum is 40.

The square root of 28239817 is about 5314.1148839670. The cubic root of 28239817 is about 304.5233691350.

The spelling of 28239817 in words is "twenty-eight million, two hundred thirty-nine thousand, eight hundred seventeen".