28681218 has 12 divisors (see below), whose sum is σ = 62142678. Its totient is φ = 9560400.

The previous prime is 28681217. The next prime is 28681283. The reversal of 28681218 is 81218682.

It can be written as a sum of positive squares in only one way, i.e., 22496049 + 6185169 = 4743^2 + 2487^2 .

It is a super-2 number, since 2×28681218² = 1645224531927048, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (28681217) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 796683 + ... + 796718.

Almost surely, 2^28681218 is an apocalyptic number.

28681218 is an abundant number, since it is smaller than the sum of its proper divisors (33461460).

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

28681218 is a wasteful number, since it uses less digits than its factorization.

28681218 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1593409 (or 1593406 counting only the distinct ones).

The product of its digits is 12288, while the sum is 36.

The square root of 28681218 is about 5355.4848519999. The cubic root of 28681218 is about 306.1017859517.

The spelling of 28681218 in words is "twenty-eight million, six hundred eighty-one thousand, two hundred eighteen".