28105811 has 8 divisors (see below), whose sum is σ = 30248064. Its totient is φ = 26017920.

The previous prime is 28105801. The next prime is 28105813. The reversal of 28105811 is 11850182.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 28105811 - 2²² = 23911507 is a prime.

It is a super-2 number, since 2×28105811² = 1579873223935442, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (28105813) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 12515 + ... + 14588.

It is an arithmetic number, because the mean of its divisors is an integer number (3781008).

Almost surely, 2^28105811 is an apocalyptic number.

28105811 is a deficient number, since it is larger than the sum of its proper divisors (2142253).

28105811 is a wasteful number, since it uses less digits than its factorization.

28105811 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 27181.

The product of its (nonzero) digits is 640, while the sum is 26.

The square root of 28105811 is about 5301.4913939381. The cubic root of 28105811 is about 304.0409217477.

Adding to 28105811 its reverse (11850182), we get a palindrome (39955993).

The spelling of 28105811 in words is "twenty-eight million, one hundred five thousand, eight hundred eleven".