28665642637 has 4 divisors (see below), whose sum is σ = 28666372896. Its totient is φ = 28664912380.

The previous prime is 28665642617. The next prime is 28665642661. The reversal of 28665642637 is 73624656682.

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.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-28665642637 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 (28665642617) 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, 302689 + ... + 385942.

It is an arithmetic number, because the mean of its divisors is an integer number (7166593224).

Almost surely, 2^28665642637 is an apocalyptic number.

It is an amenable number.

28665642637 is a deficient number, since it is larger than the sum of its proper divisors (730259).

28665642637 is an equidigital number, since it uses as much as digits as its factorization.

28665642637 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 730258.

The product of its digits is 17418240, while the sum is 55.

The spelling of 28665642637 in words is "twenty-eight billion, six hundred sixty-five million, six hundred forty-two thousand, six hundred thirty-seven".