28656163639 has 4 divisors (see below), whose sum is σ = 28657937880. Its totient is φ = 28654389400.

The previous prime is 28656163583. The next prime is 28656163727. The reversal of 28656163639 is 93636165682.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 28656163639 - 2⁹ = 28656163127 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 28656163639.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28656163139) 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, 862669 + ... + 895270.

It is an arithmetic number, because the mean of its divisors is an integer number (7164484470).

Almost surely, 2^28656163639 is an apocalyptic number.

28656163639 is a deficient number, since it is larger than the sum of its proper divisors (1774241).

28656163639 is a wasteful number, since it uses less digits than its factorization.

28656163639 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1774240.

The product of its digits is 8398080, while the sum is 55.

The spelling of 28656163639 in words is "twenty-eight billion, six hundred fifty-six million, one hundred sixty-three thousand, six hundred thirty-nine".