28278791 has 2 divisors, whose sum is σ = 28278792. Its totient is φ = 28278790.

The previous prime is 28278781. The next prime is 28278881. The reversal of 28278791 is 19787282.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-28278791 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 (28278751) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 14139395 + 14139396.

It is an arithmetic number, because the mean of its divisors is an integer number (14139396).

Almost surely, 2^28278791 is an apocalyptic number.

28278791 is a deficient number, since it is larger than the sum of its proper divisors (1).

28278791 is an equidigital number, since it uses as much as digits as its factorization.

28278791 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 112896, while the sum is 44.

The square root of 28278791 is about 5317.7806460966. The cubic root of 28278791 is about 304.6633964592.

The spelling of 28278791 in words is "twenty-eight million, two hundred seventy-eight thousand, seven hundred ninety-one".