28031887 has 4 divisors (see below), whose sum is σ = 30188200. Its totient is φ = 25875576.

The previous prime is 28031873. The next prime is 28031891. The reversal of 28031887 is 78813082.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 28031887 - 2¹¹ = 28029839 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28031837) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1078137 + ... + 1078162.

It is an arithmetic number, because the mean of its divisors is an integer number (7547050).

Almost surely, 2^28031887 is an apocalyptic number.

28031887 is a deficient number, since it is larger than the sum of its proper divisors (2156313).

28031887 is a wasteful number, since it uses less digits than its factorization.

28031887 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2156312.

The product of its (nonzero) digits is 21504, while the sum is 37.

The square root of 28031887 is about 5294.5148030769. The cubic root of 28031887 is about 303.7741245439.

The spelling of 28031887 in words is "twenty-eight million, thirty-one thousand, eight hundred eighty-seven".