28505908811 has 4 divisors (see below), whose sum is σ = 28506769272. Its totient is φ = 28505048352.

The previous prime is 28505908807. The next prime is 28505908813. The reversal of 28505908811 is 11880950582.

It is a happy number.

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

It is a cyclic number.

It is not a de Polignac number, because 28505908811 - 2² = 28505908807 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (28505908813) 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, 378461 + ... + 447486.

It is an arithmetic number, because the mean of its divisors is an integer number (7126692318).

Almost surely, 2^28505908811 is an apocalyptic number.

28505908811 is a deficient number, since it is larger than the sum of its proper divisors (860461).

28505908811 is an equidigital number, since it uses as much as digits as its factorization.

28505908811 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 860460.

The product of its (nonzero) digits is 230400, while the sum is 47.

The spelling of 28505908811 in words is "twenty-eight billion, five hundred five million, nine hundred eight thousand, eight hundred eleven".