28266581 has 12 divisors (see below), whose sum is σ = 32974272. Its totient is φ = 24160248.

The previous prime is 28266577. The next prime is 28266593. The reversal of 28266581 is 18566282.

It is not a de Polignac number, because 28266581 - 2² = 28266577 is a prime.

It is a super-2 number, since 2×28266581² = 1597999202859122, which contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28266521) 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, 25076 + ... + 26178.

It is an arithmetic number, because the mean of its divisors is an integer number (2747856).

Almost surely, 2^28266581 is an apocalyptic number.

It is an amenable number.

28266581 is a deficient number, since it is larger than the sum of its proper divisors (4707691).

28266581 is a wasteful number, since it uses less digits than its factorization.

28266581 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1640 (or 1633 counting only the distinct ones).

The product of its digits is 46080, while the sum is 38.

The square root of 28266581 is about 5316.6324868285. The cubic root of 28266581 is about 304.6195417368.

The spelling of 28266581 in words is "twenty-eight million, two hundred sixty-six thousand, five hundred eighty-one".