28278819 has 12 divisors (see below), whose sum is σ = 41716896. Its totient is φ = 18451152.

The previous prime is 28278791. The next prime is 28278881. The reversal of 28278819 is 91887282.

It is a happy number.

It is a de Polignac number, because none of the positive numbers 2^k-28278819 is a prime.

It is a super-2 number, since 2×28278819² = 1599383208069522, which contains 22 as substring.

It is a Smith number, since the sum of its digits (45) coincides with the sum of the digits of its prime factors.

It is not an unprimeable number, because it can be changed into a prime (28276819) 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 in 11 ways as a sum of consecutive naturals, for example, 33004 + ... + 33849.

It is an arithmetic number, because the mean of its divisors is an integer number (3476408).

Almost surely, 2^28278819 is an apocalyptic number.

28278819 is a deficient number, since it is larger than the sum of its proper divisors (13438077).

28278819 is a wasteful number, since it uses less digits than its factorization.

28278819 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 66906 (or 66903 counting only the distinct ones).

The product of its digits is 129024, while the sum is 45.

The square root of 28278819 is about 5317.7832787732. The cubic root of 28278819 is about 304.6634970125.

The spelling of 28278819 in words is "twenty-eight million, two hundred seventy-eight thousand, eight hundred nineteen".