28091117 has 2 divisors, whose sum is σ = 28091118. Its totient is φ = 28091116.

The previous prime is 28091093. The next prime is 28091131. The reversal of 28091117 is 71119082.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 25060036 + 3031081 = 5006^2 + 1741^2 .

It is a cyclic number.

It is not a de Polignac number, because 28091117 - 2¹² = 28087021 is a prime.

It is a super-2 number, since 2×28091117² = 1578221708615378, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 28091117.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (28091137) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 14045558 + 14045559.

It is an arithmetic number, because the mean of its divisors is an integer number (14045559).

Almost surely, 2^28091117 is an apocalyptic number.

It is an amenable number.

28091117 is a deficient number, since it is larger than the sum of its proper divisors (1).

28091117 is an equidigital number, since it uses as much as digits as its factorization.

28091117 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1008, while the sum is 29.

The square root of 28091117 is about 5300.1053763109. The cubic root of 28091117 is about 303.9879272964.

The spelling of 28091117 in words is "twenty-eight million, ninety-one thousand, one hundred seventeen".