28781516778 has 16 divisors (see below), whose sum is σ = 65786324160. Its totient is φ = 8223290496.

The previous prime is 28781516767. The next prime is 28781516833. The reversal of 28781516778 is 87761518782.

28781516778 is digitally balanced in base 5, because in such base it contains all the possibile digits an equal number of times.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 342637063 + ... + 342637146.

It is an arithmetic number, because the mean of its divisors is an integer number (4111645260).

Almost surely, 2^28781516778 is an apocalyptic number.

28781516778 is an abundant number, since it is smaller than the sum of its proper divisors (37004807382).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

28781516778 is a wasteful number, since it uses less digits than its factorization.

28781516778 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 685274221.

The product of its digits is 10536960, while the sum is 60.

The spelling of 28781516778 in words is "twenty-eight billion, seven hundred eighty-one million, five hundred sixteen thousand, seven hundred seventy-eight".