161961 has 4 divisors (see below), whose sum is σ = 215952. Its totient is φ = 107972.

The previous prime is 161957. The next prime is 161969. The reversal of 161961 is 169161.

161961 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.

It is a cyclic number.

It is not a de Polignac number, because 161961 - 2² = 161957 is a prime.

It is a D-number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (161969) 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, 26991 + ... + 26996.

It is an arithmetic number, because the mean of its divisors is an integer number (53988).

2¹⁶¹⁹⁶¹ is an apocalyptic number.

It is an amenable number.

161961 is a deficient number, since it is larger than the sum of its proper divisors (53991).

161961 is an equidigital number, since it uses as much as digits as its factorization.

161961 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 53990.

The product of its digits is 324, while the sum is 24.

The square root of 161961 is about 402.4437848942. The cubic root of 161961 is about 54.5092428843.

The spelling of 161961 in words is "one hundred sixty-one thousand, nine hundred sixty-one".