169921 has 4 divisors (see below), whose sum is σ = 170752. Its totient is φ = 169092.

The previous prime is 169919. The next prime is 169933. The reversal of 169921 is 129961.

169921 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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 a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is not a de Polignac number, because 169921 - 2¹ = 169919 is a prime.

It is an Ulam number.

It is a Duffinian number.

169921 is a lucky number.

It is a self number, because there is not a number n which added to its sum of digits gives 169921.

It is not an unprimeable number, because it can be changed into a prime (169951) 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, 136 + ... + 598.

It is an arithmetic number, because the mean of its divisors is an integer number (42688).

2¹⁶⁹⁹²¹ is an apocalyptic number.

It is an amenable number.

169921 is a deficient number, since it is larger than the sum of its proper divisors (831).

169921 is an equidigital number, since it uses as much as digits as its factorization.

169921 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 830.

The product of its digits is 972, while the sum is 28.

The square root of 169921 is about 412.2147498574. The cubic root of 169921 is about 55.3880001987.

The spelling of 169921 in words is "one hundred sixty-nine thousand, nine hundred twenty-one".