163856648561 has 4 divisors (see below), whose sum is σ = 163868297712. Its totient is φ = 163844999412.

The previous prime is 163856648513. The next prime is 163856648573. The reversal of 163856648561 is 165846658361.

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: 165846658361 = 431 ⋅384795031.

It is a cyclic number.

It is not a de Polignac number, because 163856648561 - 2⁶ = 163856648497 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 163856648561.

It is not an unprimeable number, because it can be changed into a prime (163856648861) 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, 5803451 + ... + 5831616.

It is an arithmetic number, because the mean of its divisors is an integer number (40967074428).

Almost surely, 2^163856648561 is an apocalyptic number.

It is an amenable number.

163856648561 is a deficient number, since it is larger than the sum of its proper divisors (11649151).

163856648561 is a wasteful number, since it uses less digits than its factorization.

163856648561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11649150.

The product of its digits is 24883200, while the sum is 59.

The spelling of 163856648561 in words is "one hundred sixty-three billion, eight hundred fifty-six million, six hundred forty-eight thousand, five hundred sixty-one".