28911778 has 16 divisors (see below), whose sum is σ = 51162624. Its totient is φ = 11990880.

The previous prime is 28911769. The next prime is 28911793. The reversal of 28911778 is 87711982.

It is a happy number.

It is an unprimeable number.

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 7 ways as a sum of consecutive naturals, for example, 32875 + ... + 33742.

It is an arithmetic number, because the mean of its divisors is an integer number (3197664).

Almost surely, 2^28911778 is an apocalyptic number.

28911778 is a deficient number, since it is larger than the sum of its proper divisors (22250846).

28911778 is a wasteful number, since it uses less digits than its factorization.

28911778 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 66657.

The product of its digits is 56448, while the sum is 43.

The square root of 28911778 is about 5376.9673608829. The cubic root of 28911778 is about 306.9198190588.

The spelling of 28911778 in words is "twenty-eight million, nine hundred eleven thousand, seven hundred seventy-eight".