28391871 has 8 divisors (see below), whose sum is σ = 39848320. Its totient is φ = 17931672.

The previous prime is 28391861. The next prime is 28391873. The reversal of 28391871 is 17819382.

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

It is not a de Polignac number, because 28391871 - 2¹⁵ = 28359103 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28391873) 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, 248995 + ... + 249108.

It is an arithmetic number, because the mean of its divisors is an integer number (4981040).

Almost surely, 2^28391871 is an apocalyptic number.

28391871 is a deficient number, since it is larger than the sum of its proper divisors (11456449).

28391871 is a wasteful number, since it uses less digits than its factorization.

28391871 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 498125.

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

The square root of 28391871 is about 5328.4022933709. The cubic root of 28391871 is about 305.0689479528.

The spelling of 28391871 in words is "twenty-eight million, three hundred ninety-one thousand, eight hundred seventy-one".