28780816 has 10 divisors (see below), whose sum is σ = 55762862. Its totient is φ = 14390400.

The previous prime is 28780793. The next prime is 28780819. The reversal of 28780816 is 61808782.

It can be written as a sum of positive squares in only one way, i.e., 23040000 + 5740816 = 4800^2 + 2396^2 .

It is not an unprimeable number, because it can be changed into a prime (28780819) 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, 899385 + ... + 899416.

Almost surely, 2^28780816 is an apocalyptic number.

It is an amenable number.

28780816 is a deficient number, since it is larger than the sum of its proper divisors (26982046).

28780816 is a wasteful number, since it uses less digits than its factorization.

28780816 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1798809 (or 1798803 counting only the distinct ones).

The product of its (nonzero) digits is 43008, while the sum is 40.

The square root of 28780816 is about 5364.7754845846. The cubic root of 28780816 is about 306.4556982097.

The spelling of 28780816 in words is "twenty-eight million, seven hundred eighty thousand, eight hundred sixteen".