28694347281 has 10 divisors (see below), whose sum is σ = 42864395442. Its totient is φ = 19129564800.

The previous prime is 28694347273. The next prime is 28694347343. The reversal of 28694347281 is 18274349682.

28694347281 is a `hidden beast` number, since 2 + 8 + 6 + 94 + 3 + 472 + 81 = 666.

It can be written as a sum of positive squares in only one way, i.e., 26901248256 + 1793099025 = 164016^2 + 42345^2 .

It is not a de Polignac number, because 28694347281 - 2³ = 28694347273 is a prime.

It is a super-2 number, since 2×28694347281² (a number of 22 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (28694347681) by changing a digit.

It is a polite number, since it can be written in 9 ways as a sum of consecutive naturals, for example, 177125520 + ... + 177125681.

Almost surely, 2^28694347281 is an apocalyptic number.

It is an amenable number.

28694347281 is a deficient number, since it is larger than the sum of its proper divisors (14170048161).

28694347281 is an equidigital number, since it uses as much as digits as its factorization.

28694347281 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 354251213 (or 354251204 counting only the distinct ones).

The product of its digits is 4644864, while the sum is 54.

The spelling of 28694347281 in words is "twenty-eight billion, six hundred ninety-four million, three hundred forty-seven thousand, two hundred eighty-one".