28206891 has 12 divisors (see below), whose sum is σ = 40808040. Its totient is φ = 18774720.

The previous prime is 28206889. The next prime is 28206907. The reversal of 28206891 is 19860282.

It is not a de Polignac number, because 28206891 - 2¹ = 28206889 is a prime.

It is a Smith number, since the sum of its digits (36) coincides with the sum of the digits of its prime factors.

It is not an unprimeable number, because it can be changed into a prime (28206091) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 4531 + ... + 8771.

It is an arithmetic number, because the mean of its divisors is an integer number (3400670).

Almost surely, 2^28206891 is an apocalyptic number.

28206891 is a deficient number, since it is larger than the sum of its proper divisors (12601149).

28206891 is a wasteful number, since it uses less digits than its factorization.

28206891 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4986 (or 4983 counting only the distinct ones).

The product of its (nonzero) digits is 13824, while the sum is 36.

The square root of 28206891 is about 5311.0160044948. The cubic root of 28206891 is about 304.4049708719.

The spelling of 28206891 in words is "twenty-eight million, two hundred six thousand, eight hundred ninety-one".