163642216681 has 4 divisors (see below), whose sum is σ = 168064979332. Its totient is φ = 159219454032.

The previous prime is 163642216679. The next prime is 163642216723. The reversal of 163642216681 is 186612246361.

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

It can be written as a sum of positive squares in 2 ways, for example, as 79684256656 + 83957960025 = 282284^2 + 289755^2 .

It is a cyclic number.

It is not a de Polignac number, because 163642216681 - 2¹ = 163642216679 is a prime.

It is a super-2 number, since 2×163642216681² (a number of 23 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (163642216601) 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, 2211381270 + ... + 2211381343.

It is an arithmetic number, because the mean of its divisors is an integer number (42016244833).

Almost surely, 2^163642216681 is an apocalyptic number.

It is an amenable number.

163642216681 is a deficient number, since it is larger than the sum of its proper divisors (4422762651).

163642216681 is an equidigital number, since it uses as much as digits as its factorization.

163642216681 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4422762650.

The product of its digits is 497664, while the sum is 46.

The spelling of 163642216681 in words is "one hundred sixty-three billion, six hundred forty-two million, two hundred sixteen thousand, six hundred eighty-one".