28778408165 has 16 divisors (see below), whose sum is σ = 37198617456. Its totient is φ = 21247142400.

The previous prime is 28778408161. The next prime is 28778408173. The reversal of 28778408165 is 56180487782.

It is a Cunningham number, because it is equal to 169642²+1.

It can be written as a sum of positive squares in 8 ways, for example, as 327827236 + 28450580929 = 18106^2 + 168673^2 .

It is not a de Polignac number, because 28778408165 - 2² = 28778408161 is a prime.

It is a super-2 number, since 2×28778408165² (a number of 22 digits) contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 28778408165.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28778408161) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 270425 + ... + 361505.

It is an arithmetic number, because the mean of its divisors is an integer number (2324913591).

Almost surely, 2^28778408165 is an apocalyptic number.

It is an amenable number.

28778408165 is a deficient number, since it is larger than the sum of its proper divisors (8420209291).

28778408165 is a wasteful number, since it uses less digits than its factorization.

28778408165 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 95960.

The product of its (nonzero) digits is 6021120, while the sum is 56.

The spelling of 28778408165 in words is "twenty-eight billion, seven hundred seventy-eight million, four hundred eight thousand, one hundred sixty-five".