163921 has 4 divisors (see below), whose sum is σ = 171072. Its totient is φ = 156772.

The previous prime is 163909. The next prime is 163927. The reversal of 163921 is 129361.

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 not a de Polignac number, because 163921 - 2⁹ = 163409 is a prime.

It is a Smith number, since the sum of its digits (22) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 163892 and 163901.

It is not an unprimeable number, because it can be changed into a prime (163927) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (5) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3541 + ... + 3586.

It is an arithmetic number, because the mean of its divisors is an integer number (42768).

2¹⁶³⁹²¹ is an apocalyptic number.

It is an amenable number.

163921 is a deficient number, since it is larger than the sum of its proper divisors (7151).

163921 is an equidigital number, since it uses as much as digits as its factorization.

163921 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7150.

The product of its digits is 324, while the sum is 22.

The square root of 163921 is about 404.8715845796. The cubic root of 163921 is about 54.7282462593.

The spelling of 163921 in words is "one hundred sixty-three thousand, nine hundred twenty-one".