28491205 has 8 divisors (see below), whose sum is σ = 34439832. Its totient is φ = 22626048.

The previous prime is 28491193. The next prime is 28491223. The reversal of 28491205 is 50219482.

It can be written as a sum of positive squares in 4 ways, for example, as 1127844 + 27363361 = 1062^2 + 5231^2 .

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-28491205 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 20112 + ... + 21481.

It is an arithmetic number, because the mean of its divisors is an integer number (4304979).

Almost surely, 2^28491205 is an apocalyptic number.

It is an amenable number.

28491205 is a deficient number, since it is larger than the sum of its proper divisors (5948627).

28491205 is a wasteful number, since it uses less digits than its factorization.

28491205 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 41735.

The product of its (nonzero) digits is 5760, while the sum is 31.

The square root of 28491205 is about 5337.7153352347. The cubic root of 28491205 is about 305.4243131256.

The spelling of 28491205 in words is "twenty-eight million, four hundred ninety-one thousand, two hundred five".