28116321 has 8 divisors (see below), whose sum is σ = 37820640. Its totient is φ = 18578112.

The previous prime is 28116313. The next prime is 28116353. The reversal of 28116321 is 12361182.

Added to its reverse (12361182) it gives a triangular number (40477503 = T₈₉₉₇).

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

It is not a de Polignac number, because 28116321 - 2³ = 28116313 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 28116291 and 28116300.

It is not an unprimeable number, because it can be changed into a prime (28116301) 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 in 7 ways as a sum of consecutive naturals, for example, 41131 + ... + 41808.

It is an arithmetic number, because the mean of its divisors is an integer number (4727580).

Almost surely, 2^28116321 is an apocalyptic number.

It is an amenable number.

28116321 is a deficient number, since it is larger than the sum of its proper divisors (9704319).

28116321 is a wasteful number, since it uses less digits than its factorization.

28116321 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 83055.

The product of its digits is 576, while the sum is 24.

The square root of 28116321 is about 5302.4825317958. The cubic root of 28116321 is about 304.0788151198.

Adding to 28116321 its reverse (12361182), we get a triangular number (40477503 = T₈₉₉₇).

The spelling of 28116321 in words is "twenty-eight million, one hundred sixteen thousand, three hundred twenty-one".