28039291 has 4 divisors (see below), whose sum is σ = 32044912. Its totient is φ = 24033672.

The previous prime is 28039289. The next prime is 28039313. The reversal of 28039291 is 19293082.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 19293082 = 2 ⋅9646541.

It is a cyclic number.

It is not a de Polignac number, because 28039291 - 2¹ = 28039289 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (28039211) 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, 2002800 + ... + 2002813.

It is an arithmetic number, because the mean of its divisors is an integer number (8011228).

Almost surely, 2^28039291 is an apocalyptic number.

28039291 is a deficient number, since it is larger than the sum of its proper divisors (4005621).

28039291 is an equidigital number, since it uses as much as digits as its factorization.

28039291 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4005620.

The product of its (nonzero) digits is 7776, while the sum is 34.

The square root of 28039291 is about 5295.2139711252. The cubic root of 28039291 is about 303.8008672509.

The spelling of 28039291 in words is "twenty-eight million, thirty-nine thousand, two hundred ninety-one".