28280266681 has 4 divisors (see below), whose sum is σ = 28282704372. Its totient is φ = 28277828992.

The previous prime is 28280266673. The next prime is 28280266727. The reversal of 28280266681 is 18666208282.

It is a happy number.

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 10098441081 + 18181825600 = 100491^2 + 134840^2 .

It is a cyclic number.

It is not a de Polignac number, because 28280266681 - 2³ = 28280266673 is a prime.

It is a super-2 number, since 2×28280266681² (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 (28280266601) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1201360 + ... + 1224673.

It is an arithmetic number, because the mean of its divisors is an integer number (7070676093).

Almost surely, 2^28280266681 is an apocalyptic number.

It is an amenable number.

28280266681 is a deficient number, since it is larger than the sum of its proper divisors (2437691).

28280266681 is a wasteful number, since it uses less digits than its factorization.

28280266681 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2437690.

The product of its (nonzero) digits is 884736, while the sum is 49.

The spelling of 28280266681 in words is "twenty-eight billion, two hundred eighty million, two hundred sixty-six thousand, six hundred eighty-one".