28686788 has 24 divisors (see below), whose sum is σ = 54257112. Its totient is φ = 13192704.

The previous prime is 28686767. The next prime is 28686793. The reversal of 28686788 is 88768682.

It can be written as a sum of positive squares in 4 ways, for example, as 1459264 + 27227524 = 1208^2 + 5218^2 .

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 16706 + ... + 18342.

It is an arithmetic number, because the mean of its divisors is an integer number (2260713).

Almost surely, 2^28686788 is an apocalyptic number.

It is an amenable number.

28686788 is a deficient number, since it is larger than the sum of its proper divisors (25570324).

28686788 is a wasteful number, since it uses less digits than its factorization.

28686788 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1991 (or 1989 counting only the distinct ones).

The product of its digits is 2064384, while the sum is 53.

The square root of 28686788 is about 5356.0048543667. The cubic root of 28686788 is about 306.1216000403.

The spelling of 28686788 in words is "twenty-eight million, six hundred eighty-six thousand, seven hundred eighty-eight".