28156218 has 16 divisors (see below), whose sum is σ = 56946240. Its totient is φ = 9279776.

The previous prime is 28156213. The next prime is 28156231. The reversal of 28156218 is 81265182.

It is a super-2 number, since 2×28156218² = 1585545224127048, which contains 22 as substring.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (28156213) 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 7 ways as a sum of consecutive naturals, for example, 25830 + ... + 26897.

It is an arithmetic number, because the mean of its divisors is an integer number (3559140).

Almost surely, 2^28156218 is an apocalyptic number.

28156218 is an abundant number, since it is smaller than the sum of its proper divisors (28790022).

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

28156218 is a wasteful number, since it uses less digits than its factorization.

28156218 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 52821.

The product of its digits is 7680, while the sum is 33.

The square root of 28156218 is about 5306.2433038827. The cubic root of 28156218 is about 304.2225762074. Note that the first 3 decimals are identical.

The spelling of 28156218 in words is "twenty-eight million, one hundred fifty-six thousand, two hundred eighteen".