28721844778 has 24 divisors (see below), whose sum is σ = 47452872096. Its totient is φ = 13028522760.

The previous prime is 28721844769. The next prime is 28721844793. The reversal of 28721844778 is 87744812782.

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 11 ways as a sum of consecutive naturals, for example, 4000 + ... + 239707.

It is an arithmetic number, because the mean of its divisors is an integer number (1977203004).

Almost surely, 2^28721844778 is an apocalyptic number.

28721844778 is a deficient number, since it is larger than the sum of its proper divisors (18731027318).

28721844778 is a wasteful number, since it uses less digits than its factorization.

28721844778 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 244218 (or 244207 counting only the distinct ones).

The product of its digits is 11239424, while the sum is 58.

The spelling of 28721844778 in words is "twenty-eight billion, seven hundred twenty-one million, eight hundred forty-four thousand, seven hundred seventy-eight".