161906 has 4 divisors (see below), whose sum is σ = 242862. Its totient is φ = 80952.

The previous prime is 161881. The next prime is 161911. The reversal of 161906 is 609161.

161906 is nontrivially palindromic in base 16.

161906 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.

It can be written as a sum of positive squares in only one way, i.e., 152881 + 9025 = 391^2 + 95^2 .

It is an Ulam number.

It is an unprimeable number.

161906 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40475 + ... + 40478.

2¹⁶¹⁹⁰⁶ is an apocalyptic number.

161906 is a deficient number, since it is larger than the sum of its proper divisors (80956).

161906 is an equidigital number, since it uses as much as digits as its factorization.

161906 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 80955.

The product of its (nonzero) digits is 324, while the sum is 23.

The square root of 161906 is about 402.3754465670. The cubic root of 161906 is about 54.5030719588.

The spelling of 161906 in words is "one hundred sixty-one thousand, nine hundred six".