28391291 has 8 divisors (see below), whose sum is σ = 28968384. Its totient is φ = 27817920.

The previous prime is 28391287. The next prime is 28391303. The reversal of 28391291 is 19219382.

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 28391291 - 2² = 28391287 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (28391281) 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, 18350 + ... + 19836.

It is an arithmetic number, because the mean of its divisors is an integer number (3621048).

Almost surely, 2^28391291 is an apocalyptic number.

28391291 is a deficient number, since it is larger than the sum of its proper divisors (577093).

28391291 is a wasteful number, since it uses less digits than its factorization.

28391291 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1861.

The product of its digits is 7776, while the sum is 35.

The square root of 28391291 is about 5328.3478677729. The cubic root of 28391291 is about 305.0668705836.

It can be divided in two parts, 28391 and 291, that added together give a palindrome (28682).

The spelling of 28391291 in words is "twenty-eight million, three hundred ninety-one thousand, two hundred ninety-one".