181501 has 2 divisors, whose sum is σ = 181502. Its totient is φ = 181500.

The previous prime is 181499. The next prime is 181513. The reversal of 181501 is 105181.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 181476 + 25 = 426^2 + 5^2 .

It is a cyclic number.

It is not a de Polignac number, because 181501 - 2¹ = 181499 is a prime.

It is a super-2 number, since 2×181501² = 65885226002, which contains 22 as substring.

Together with 181499, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (181001) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 90750 + 90751.

It is an arithmetic number, because the mean of its divisors is an integer number (90751).

2¹⁸¹⁵⁰¹ is an apocalyptic number.

It is an amenable number.

181501 is a deficient number, since it is larger than the sum of its proper divisors (1).

181501 is an equidigital number, since it uses as much as digits as its factorization.

181501 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 40, while the sum is 16.

The square root of 181501 is about 426.0293417125. The cubic root of 181501 is about 56.6186713945.

Adding to 181501 its reverse (105181), we get a palindrome (286682).

The spelling of 181501 in words is "one hundred eighty-one thousand, five hundred one".