28518581 has 12 divisors (see below), whose sum is σ = 35294112. Its totient is φ = 22563216.

The previous prime is 28518559. The next prime is 28518587. The reversal of 28518581 is 18581582.

It is not a de Polignac number, because 28518581 - 2¹⁴ = 28502197 is a prime.

It is a super-2 number, since 2×28518581² = 1626618924507122, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28518587) 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 11 ways as a sum of consecutive naturals, for example, 10871 + ... + 13236.

It is an arithmetic number, because the mean of its divisors is an integer number (2941176).

Almost surely, 2^28518581 is an apocalyptic number.

It is an amenable number.

28518581 is a deficient number, since it is larger than the sum of its proper divisors (6775531).

28518581 is a wasteful number, since it uses less digits than its factorization.

28518581 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 24140 (or 24127 counting only the distinct ones).

The product of its digits is 25600, while the sum is 38.

The square root of 28518581 is about 5340.2791125558. The cubic root of 28518581 is about 305.5221049344.

The spelling of 28518581 in words is "twenty-eight million, five hundred eighteen thousand, five hundred eighty-one".