28006691905 has 16 divisors (see below), whose sum is σ = 35596409040. Its totient is φ = 21080614912.

The previous prime is 28006691861. The next prime is 28006691941. The reversal of 28006691905 is 50919660082.

It is a Cunningham number, because it is equal to 167352²+1.

It can be written as a sum of positive squares in 8 ways, for example, as 1 + 28006691904 = 1^2 + 167352^2 .

It is a cyclic number.

It is not a de Polignac number, because 28006691905 - 2⁷ = 28006691777 is a prime.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 221427 + ... + 324103.

It is an arithmetic number, because the mean of its divisors is an integer number (2224775565).

Almost surely, 2^28006691905 is an apocalyptic number.

It is an amenable number.

28006691905 is a deficient number, since it is larger than the sum of its proper divisors (7589717135).

28006691905 is a wasteful number, since it uses less digits than its factorization.

28006691905 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 105908.

The product of its (nonzero) digits is 233280, while the sum is 46.

The spelling of 28006691905 in words is "twenty-eight billion, six million, six hundred ninety-one thousand, nine hundred five".