28317891 has 16 divisors (see below), whose sum is σ = 44640000. Its totient is φ = 15623328.

The previous prime is 28317881. The next prime is 28317907. The reversal of 28317891 is 19871382.

It is not a de Polignac number, because 28317891 - 2⁹ = 28317379 is a prime.

It is not an unprimeable number, because it can be changed into a prime (28317881) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 22641 + ... + 23858.

It is an arithmetic number, because the mean of its divisors is an integer number (2790000).

Almost surely, 2^28317891 is an apocalyptic number.

28317891 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

28317891 is a deficient number, since it is larger than the sum of its proper divisors (16322109).

28317891 is a wasteful number, since it uses less digits than its factorization.

28317891 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 46538.

The product of its digits is 24192, while the sum is 39.

The square root of 28317891 is about 5321.4557218866. The cubic root of 28317891 is about 304.8037472586.

The spelling of 28317891 in words is "twenty-eight million, three hundred seventeen thousand, eight hundred ninety-one".