28181218 has 16 divisors (see below), whose sum is σ = 47920320. Its totient is φ = 12321936.

The previous prime is 28181203. The next prime is 28181287. The reversal of 28181218 is 81218182.

It is a happy number.

It is a self number, because there is not a number n which added to its sum of digits gives 28181218.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 28030 + ... + 29017.

It is an arithmetic number, because the mean of its divisors is an integer number (2995020).

Almost surely, 2^28181218 is an apocalyptic number.

28181218 is a deficient number, since it is larger than the sum of its proper divisors (19739102).

28181218 is a wasteful number, since it uses less digits than its factorization.

28181218 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 57081.

The product of its digits is 2048, while the sum is 31.

The square root of 28181218 is about 5308.5984967786. The cubic root of 28181218 is about 304.3125896520.

The spelling of 28181218 in words is "twenty-eight million, one hundred eighty-one thousand, two hundred eighteen".