28278794569 has 9 divisors (see below), whose sum is σ = 28419910407. Its totient is φ = 28138378464.

The previous prime is 28278794567. The next prime is 28278794573. The reversal of 28278794569 is 96549787282.

The square root of 28278794569 is 168163.

It is a perfect power (a square), and thus also a powerful number.

It can be written as a sum of positive squares in only one way, i.e., 7625655625 + 20653138944 = 87325^2 + 143712^2 .

It is not a de Polignac number, because 28278794569 - 2¹ = 28278794567 is a prime.

It is a super-2 number, since 2×28278794569² (a number of 22 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (28278794567) by changing a digit.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 56670682 + ... + 56671180.

It is an arithmetic number, because the mean of its divisors is an integer number (3157767823).

Almost surely, 2^28278794569 is an apocalyptic number.

28278794569 is the 168163-rd square number.

28278794569 is the 84082-nd centered octagonal number.

It is an amenable number.

28278794569 is a deficient number, since it is larger than the sum of its proper divisors (141115838).

28278794569 is an frugal number, since it uses more digits than its factorization.

28278794569 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1672 (or 836 counting only the distinct ones).

The product of its digits is 121927680, while the sum is 67.

The spelling of 28278794569 in words is "twenty-eight billion, two hundred seventy-eight million, seven hundred ninety-four thousand, five hundred sixty-nine".