181001 has 2 divisors, whose sum is σ = 181002. Its totient is φ = 181000.

The previous prime is 180959. The next prime is 181003. The reversal of 181001 is 100181.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 179776 + 1225 = 424^2 + 35^2 .

It is a cyclic number.

It is not a de Polignac number, because 181001 - 2¹⁴ = 164617 is a prime.

It is a super-2 number, since 2×181001² = 65522724002, which contains 22 as substring.

It is a Sophie Germain prime.

Together with 181003, it forms a pair of twin primes.

It is a Chen prime.

It is a Curzon number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 181001.

It is not a weakly prime, because it can be changed into another prime (181003) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 90500 + 90501.

It is an arithmetic number, because the mean of its divisors is an integer number (90501).

2¹⁸¹⁰⁰¹ is an apocalyptic number.

It is an amenable number.

181001 is a deficient number, since it is larger than the sum of its proper divisors (1).

181001 is an equidigital number, since it uses as much as digits as its factorization.

181001 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 8, while the sum is 11.

The square root of 181001 is about 425.4421229733. The cubic root of 181001 is about 56.5666324321.

Adding to 181001 its reverse (100181), we get a palindrome (281182).

The spelling of 181001 in words is "one hundred eighty-one thousand, one".