28189505 has 8 divisors (see below), whose sum is σ = 33973992. Its totient is φ = 22453888.

The previous prime is 28189493. The next prime is 28189517. The reversal of 28189505 is 50598182.

It is an interprime number because it is at equal distance from previous prime (28189493) and next prime (28189517).

It can be written as a sum of positive squares in 4 ways, for example, as 14641 + 28174864 = 121^2 + 5308^2 .

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-28189505 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 10934 + ... + 13263.

It is an arithmetic number, because the mean of its divisors is an integer number (4246749).

Almost surely, 2^28189505 is an apocalyptic number.

It is an amenable number.

28189505 is a deficient number, since it is larger than the sum of its proper divisors (5784487).

28189505 is a wasteful number, since it uses less digits than its factorization.

28189505 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 24435.

The product of its (nonzero) digits is 28800, while the sum is 38.

The square root of 28189505 is about 5309.3789655665. The cubic root of 28189505 is about 304.3424155604.

The spelling of 28189505 in words is "twenty-eight million, one hundred eighty-nine thousand, five hundred five".