28778775 has 24 divisors (see below), whose sum is σ = 47794560. Its totient is φ = 15279840.

The previous prime is 28778747. The next prime is 28778777. The reversal of 28778775 is 57787782.

It is not a de Polignac number, because 28778775 - 2⁷ = 28778647 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28778777) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 18996 + ... + 20454.

It is an arithmetic number, because the mean of its divisors is an integer number (1991440).

Almost surely, 2^28778775 is an apocalyptic number.

28778775 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

28778775 is a deficient number, since it is larger than the sum of its proper divisors (19015785).

28778775 is a wasteful number, since it uses less digits than its factorization.

28778775 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1735 (or 1730 counting only the distinct ones).

The product of its digits is 1536640, while the sum is 51.

The square root of 28778775 is about 5364.5852588993. The cubic root of 28778775 is about 306.4484539066.

The spelling of 28778775 in words is "twenty-eight million, seven hundred seventy-eight thousand, seven hundred seventy-five".