28188031 has 4 divisors (see below), whose sum is σ = 28410112. Its totient is φ = 27965952.

The previous prime is 28188019. The next prime is 28188037. The reversal of 28188031 is 13088182.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-28188031 is a prime.

It is a super-2 number, since 2×28188031² = 1589130183313922, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 28187984 and 28188002.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28188037) 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, 110850 + ... + 111103.

It is an arithmetic number, because the mean of its divisors is an integer number (7102528).

Almost surely, 2^28188031 is an apocalyptic number.

28188031 is a deficient number, since it is larger than the sum of its proper divisors (222081).

28188031 is a wasteful number, since it uses less digits than its factorization.

28188031 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 222080.

The product of its (nonzero) digits is 3072, while the sum is 31.

The square root of 28188031 is about 5309.2401527902. The cubic root of 28188031 is about 304.3371108848.

The spelling of 28188031 in words is "twenty-eight million, one hundred eighty-eight thousand, thirty-one".