28471891 has 12 divisors (see below), whose sum is σ = 33893112. Its totient is φ = 23835168.

The previous prime is 28471871. The next prime is 28471903. The reversal of 28471891 is 19817482.

It is a happy number.

It is not a de Polignac number, because 28471891 - 2¹⁵ = 28439123 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (28471841) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 4650 + ... + 8863.

It is an arithmetic number, because the mean of its divisors is an integer number (2824426).

Almost surely, 2^28471891 is an apocalyptic number.

28471891 is a deficient number, since it is larger than the sum of its proper divisors (5421221).

28471891 is a wasteful number, since it uses less digits than its factorization.

28471891 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13570 (or 13563 counting only the distinct ones).

The product of its digits is 32256, while the sum is 40.

The square root of 28471891 is about 5335.9058275048. The cubic root of 28471891 is about 305.3552824821.

The spelling of 28471891 in words is "twenty-eight million, four hundred seventy-one thousand, eight hundred ninety-one".