28218918 has 32 divisors (see below), whose sum is σ = 69463296. Its totient is φ = 7442208.

The previous prime is 28218899. The next prime is 28218919. The reversal of 28218918 is 81981282.

It is a Smith number, since the sum of its digits (39) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Harshad number since it is a multiple of its sum of digits (39).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28218919) 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 15 ways as a sum of consecutive naturals, for example, 25296 + ... + 26387.

It is an arithmetic number, because the mean of its divisors is an integer number (2170728).

Almost surely, 2^28218918 is an apocalyptic number.

28218918 is an abundant number, since it is smaller than the sum of its proper divisors (41244378).

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

28218918 is a wasteful number, since it uses less digits than its factorization.

28218918 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 51708.

The product of its digits is 18432, while the sum is 39.

The square root of 28218918 is about 5312.1481530545. The cubic root of 28218918 is about 304.4482293126.

The spelling of 28218918 in words is "twenty-eight million, two hundred eighteen thousand, nine hundred eighteen".