28032778 has 8 divisors (see below), whose sum is σ = 42119172. Its totient is φ = 13993056.

The previous prime is 28032769. The next prime is 28032793. The reversal of 28032778 is 87723082.

It can be written as a sum of positive squares in 2 ways, for example, as 23980609 + 4052169 = 4897^2 + 2013^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 10125 + ... + 12592.

Almost surely, 2^28032778 is an apocalyptic number.

28032778 is a deficient number, since it is larger than the sum of its proper divisors (14086394).

28032778 is a wasteful number, since it uses less digits than its factorization.

28032778 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 23336.

The product of its (nonzero) digits is 37632, while the sum is 37.

The square root of 28032778 is about 5294.5989460959. The cubic root of 28032778 is about 303.7773430200. Note that the first 3 decimals are identical.

The spelling of 28032778 in words is "twenty-eight million, thirty-two thousand, seven hundred seventy-eight".