28181886 has 16 divisors (see below), whose sum is σ = 59679504. Its totient is φ = 8841344.

The previous prime is 28181863. The next prime is 28181891. The reversal of 28181886 is 68818182.

It is a Smith number, since the sum of its digits (42) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Curzon number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 138045 + ... + 138248.

It is an arithmetic number, because the mean of its divisors is an integer number (3729969).

Almost surely, 2^28181886 is an apocalyptic number.

28181886 is an abundant number, since it is smaller than the sum of its proper divisors (31497618).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

28181886 is a wasteful number, since it uses less digits than its factorization.

28181886 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 276315.

The product of its digits is 49152, while the sum is 42.

The square root of 28181886 is about 5308.6614132001. The cubic root of 28181886 is about 304.3149940809.

The spelling of 28181886 in words is "twenty-eight million, one hundred eighty-one thousand, eight hundred eighty-six".