181669 has 2 divisors, whose sum is σ = 181670. Its totient is φ = 181668.

The previous prime is 181667. The next prime is 181693. The reversal of 181669 is 966181.

It is a happy number.

181669 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 131044 + 50625 = 362^2 + 225^2 .

It is a cyclic number.

It is not a de Polignac number, because 181669 - 2¹ = 181667 is a prime.

It is a super-2 number, since 2×181669² = 66007251122, which contains 22 as substring.

Together with 181667, it forms a pair of twin primes.

It is an Ulam number.

It is a self number, because there is not a number n which added to its sum of digits gives 181669.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (181667) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 90834 + 90835.

It is an arithmetic number, because the mean of its divisors is an integer number (90835).

2¹⁸¹⁶⁶⁹ is an apocalyptic number.

It is an amenable number.

181669 is a deficient number, since it is larger than the sum of its proper divisors (1).

181669 is an equidigital number, since it uses as much as digits as its factorization.

181669 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 2592, while the sum is 31.

The square root of 181669 is about 426.2264656260. The cubic root of 181669 is about 56.6361350329.

The spelling of 181669 in words is "one hundred eighty-one thousand, six hundred sixty-nine".