28320751 has 4 divisors (see below), whose sum is σ = 29552112. Its totient is φ = 27089392.

The previous prime is 28320749. The next prime is 28320769. The reversal of 28320751 is 15702382.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 15702382 = 2 ⋅7851191.

It is a cyclic number.

It is not a de Polignac number, because 28320751 - 2¹ = 28320749 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28320731) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 615646 + ... + 615691.

It is an arithmetic number, because the mean of its divisors is an integer number (7388028).

Almost surely, 2^28320751 is an apocalyptic number.

28320751 is a deficient number, since it is larger than the sum of its proper divisors (1231361).

28320751 is a wasteful number, since it uses less digits than its factorization.

28320751 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1231360.

The product of its (nonzero) digits is 3360, while the sum is 28.

The square root of 28320751 is about 5321.7244385631. The cubic root of 28320751 is about 304.8140082555.

The spelling of 28320751 in words is "twenty-eight million, three hundred twenty thousand, seven hundred fifty-one".