181961 has 4 divisors (see below), whose sum is σ = 195972. Its totient is φ = 167952.

The previous prime is 181957. The next prime is 181967. The reversal of 181961 is 169181.

181961 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 2 ways, for example, as 55225 + 126736 = 235^2 + 356^2 .

It is a cyclic number.

It is not a de Polignac number, because 181961 - 2² = 181957 is a prime.

It is a Duffinian number.

It is a plaindrome in base 11.

It is a nialpdrome in base 8.

It is a self number, because there is not a number n which added to its sum of digits gives 181961.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (181967) 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, 6986 + ... + 7011.

It is an arithmetic number, because the mean of its divisors is an integer number (48993).

2¹⁸¹⁹⁶¹ is an apocalyptic number.

It is an amenable number.

181961 is a deficient number, since it is larger than the sum of its proper divisors (14011).

181961 is a wasteful number, since it uses less digits than its factorization.

181961 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 14010.

The product of its digits is 432, while the sum is 26.

The square root of 181961 is about 426.5688690001. The cubic root of 181961 is about 56.6664628982. Note that the first 3 decimals are identical.

The spelling of 181961 in words is "one hundred eighty-one thousand, nine hundred sixty-one".