28159881 has 16 divisors (see below), whose sum is σ = 39690240. Its totient is φ = 17709840.

The previous prime is 28159877. The next prime is 28159897. The reversal of 28159881 is 18895182.

It is not a de Polignac number, because 28159881 - 2² = 28159877 is a prime.

It is a super-2 number, since 2×28159881² = 1585957795868322, which contains 22 as substring.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (28159861) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 14536 + ... + 16358.

It is an arithmetic number, because the mean of its divisors is an integer number (2480640).

Almost surely, 2^28159881 is an apocalyptic number.

It is an amenable number.

28159881 is a deficient number, since it is larger than the sum of its proper divisors (11530359).

28159881 is a wasteful number, since it uses less digits than its factorization.

28159881 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2116.

The product of its digits is 46080, while the sum is 42.

The square root of 28159881 is about 5306.5884521037. The cubic root of 28159881 is about 304.2357683079.

The spelling of 28159881 in words is "twenty-eight million, one hundred fifty-nine thousand, eight hundred eighty-one".