163681 has 8 divisors (see below), whose sum is σ = 190400. Its totient is φ = 137808.

The previous prime is 163679. The next prime is 163697. The reversal of 163681 is 186361.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 163681 - 2¹ = 163679 is a prime.

It is a super-2 number, since 2×163681² = 53582939522, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (163601) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 295 + ... + 643.

It is an arithmetic number, because the mean of its divisors is an integer number (23800).

2¹⁶³⁶⁸¹ is an apocalyptic number.

It is an amenable number.

163681 is a deficient number, since it is larger than the sum of its proper divisors (26719).

163681 is an equidigital number, since it uses as much as digits as its factorization.

163681 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 423.

The product of its digits is 864, while the sum is 25.

The square root of 163681 is about 404.5750857381. The cubic root of 163681 is about 54.7015236417.

The spelling of 163681 in words is "one hundred sixty-three thousand, six hundred eighty-one".