28776321 has 12 divisors (see below), whose sum is σ = 47503872. Its totient is φ = 16443576.

The previous prime is 28776283. The next prime is 28776329. The reversal of 28776321 is 12367782.

It is not a de Polignac number, because 28776321 - 2⁷ = 28776193 is a prime.

It is not an unprimeable number, because it can be changed into a prime (28776329) 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 11 ways as a sum of consecutive naturals, for example, 228321 + ... + 228446.

It is an arithmetic number, because the mean of its divisors is an integer number (3958656).

Almost surely, 2^28776321 is an apocalyptic number.

28776321 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

It is an amenable number.

28776321 is a deficient number, since it is larger than the sum of its proper divisors (18727551).

28776321 is a wasteful number, since it uses less digits than its factorization.

28776321 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 456780 (or 456777 counting only the distinct ones).

The product of its digits is 28224, while the sum is 36.

The square root of 28776321 is about 5364.3565317753. The cubic root of 28776321 is about 306.4397432523.

The spelling of 28776321 in words is "twenty-eight million, seven hundred seventy-six thousand, three hundred twenty-one".