28261643 has 4 divisors (see below), whose sum is σ = 28272888. Its totient is φ = 28250400.

The previous prime is 28261637. The next prime is 28261657. The reversal of 28261643 is 34616282.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is not a de Polignac number, because 28261643 - 2⁴ = 28261627 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (28261603) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 68 + ... + 7518.

It is an arithmetic number, because the mean of its divisors is an integer number (7068222).

Almost surely, 2^28261643 is an apocalyptic number.

28261643 is a deficient number, since it is larger than the sum of its proper divisors (11245).

28261643 is an equidigital number, since it uses as much as digits as its factorization.

28261643 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11244.

The product of its digits is 13824, while the sum is 32.

The square root of 28261643 is about 5316.1680748449. The cubic root of 28261643 is about 304.6018023093.

The spelling of 28261643 in words is "twenty-eight million, two hundred sixty-one thousand, six hundred forty-three".