28293391 has 8 divisors (see below), whose sum is σ = 32883840. Its totient is φ = 23840088.

The previous prime is 28293347. The next prime is 28293407. The reversal of 28293391 is 19339282.

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

It is a cyclic number.

It is not a de Polignac number, because 28293391 - 2⁷ = 28293263 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 28293391.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28293301) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 33841 + ... + 34666.

It is an arithmetic number, because the mean of its divisors is an integer number (4110480).

Almost surely, 2^28293391 is an apocalyptic number.

28293391 is a deficient number, since it is larger than the sum of its proper divisors (4590449).

28293391 is an equidigital number, since it uses as much as digits as its factorization.

28293391 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 68573.

The product of its digits is 23328, while the sum is 37.

The square root of 28293391 is about 5319.1532220834. The cubic root of 28293391 is about 304.7158187889.

It can be divided in two parts, 282933 and 91, that added together give a square (283024 = 532²).

The spelling of 28293391 in words is "twenty-eight million, two hundred ninety-three thousand, three hundred ninety-one".