28120939811 has 4 divisors (see below), whose sum is σ = 29343589392. Its totient is φ = 26898290232.

The previous prime is 28120939801. The next prime is 28120939813. The reversal of 28120939811 is 11893902182.

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 28120939811 - 2²⁶ = 28053830947 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (28120939813) 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, 611324756 + ... + 611324801.

It is an arithmetic number, because the mean of its divisors is an integer number (7335897348).

Almost surely, 2^28120939811 is an apocalyptic number.

28120939811 is a deficient number, since it is larger than the sum of its proper divisors (1222649581).

28120939811 is a wasteful number, since it uses less digits than its factorization.

28120939811 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1222649580.

The product of its (nonzero) digits is 62208, while the sum is 44.

The spelling of 28120939811 in words is "twenty-eight billion, one hundred twenty million, nine hundred thirty-nine thousand, eight hundred eleven".