28161020777 has 4 divisors (see below), whose sum is σ = 28166568276. Its totient is φ = 28155473280.

The previous prime is 28161020773. The next prime is 28161020779. The reversal of 28161020777 is 77702016182.

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

It can be written as a sum of positive squares in 2 ways, for example, as 10993732201 + 17167288576 = 104851^2 + 131024^2 .

It is a cyclic number.

It is not a de Polignac number, because 28161020777 - 2² = 28161020773 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (28161020773) 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, 2766128 + ... + 2776289.

It is an arithmetic number, because the mean of its divisors is an integer number (7041642069).

Almost surely, 2^28161020777 is an apocalyptic number.

It is an amenable number.

28161020777 is a deficient number, since it is larger than the sum of its proper divisors (5547499).

28161020777 is an equidigital number, since it uses as much as digits as its factorization.

28161020777 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5547498.

The product of its (nonzero) digits is 65856, while the sum is 41.

The spelling of 28161020777 in words is "twenty-eight billion, one hundred sixty-one million, twenty thousand, seven hundred seventy-seven".