28169947 has 4 divisors (see below), whose sum is σ = 30336880. Its totient is φ = 26003016.

The previous prime is 28169903. The next prime is 28169971. The reversal of 28169947 is 74996182.

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

It is a de Polignac number, because none of the positive numbers 2^k-28169947 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 28169897 and 28169906.

It is not an unprimeable number, because it can be changed into a prime (28169147) 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, 1083447 + ... + 1083472.

It is an arithmetic number, because the mean of its divisors is an integer number (7584220).

Almost surely, 2^28169947 is an apocalyptic number.

28169947 is a deficient number, since it is larger than the sum of its proper divisors (2166933).

28169947 is a wasteful number, since it uses less digits than its factorization.

28169947 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2166932.

The product of its digits is 217728, while the sum is 46.

The square root of 28169947 is about 5307.5368109887. The cubic root of 28169947 is about 304.2720145834.

The spelling of 28169947 in words is "twenty-eight million, one hundred sixty-nine thousand, nine hundred forty-seven".