28320437 has 4 divisors (see below), whose sum is σ = 28332876. Its totient is φ = 28308000.

The previous prime is 28320427. The next prime is 28320449. The reversal of 28320437 is 73402382.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It can be written as a sum of positive squares in 2 ways, for example, as 15689521 + 12630916 = 3961^2 + 3554^2 .

It is a cyclic number.

It is not a de Polignac number, because 28320437 - 2⁴ = 28320421 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 (28320407) 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 3 ways as a sum of consecutive naturals, for example, 1718 + ... + 7719.

It is an arithmetic number, because the mean of its divisors is an integer number (7083219).

Almost surely, 2^28320437 is an apocalyptic number.

It is an amenable number.

28320437 is a deficient number, since it is larger than the sum of its proper divisors (12439).

28320437 is an equidigital number, since it uses as much as digits as its factorization.

28320437 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12438.

The product of its (nonzero) digits is 8064, while the sum is 29.

The square root of 28320437 is about 5321.6949367659. The cubic root of 28320437 is about 304.8128817323.

The spelling of 28320437 in words is "twenty-eight million, three hundred twenty thousand, four hundred thirty-seven".