28666766693 has 4 divisors (see below), whose sum is σ = 28667690688. Its totient is φ = 28665842700.

The previous prime is 28666766683. The next prime is 28666766731. The reversal of 28666766693 is 39666766682.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 39666766682 = 2 ⋅19833383341.

It is a cyclic number.

It is not a de Polignac number, because 28666766693 - 2⁸ = 28666766437 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28666766683) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 413783 + ... + 478068.

It is an arithmetic number, because the mean of its divisors is an integer number (7166922672).

Almost surely, 2^28666766693 is an apocalyptic number.

It is an amenable number.

28666766693 is a deficient number, since it is larger than the sum of its proper divisors (923995).

28666766693 is an equidigital number, since it uses as much as digits as its factorization.

28666766693 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 923994.

The product of its digits is 141087744, while the sum is 65.

The spelling of 28666766693 in words is "twenty-eight billion, six hundred sixty-six million, seven hundred sixty-six thousand, six hundred ninety-three".