1680181 has 2 divisors, whose sum is σ = 1680182. Its totient is φ = 1680180.

The previous prime is 1680179. The next prime is 1680191. The reversal of 1680181 is 1810861.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1512900 + 167281 = 1230^2 + 409^2 .

It is a cyclic number.

It is not a de Polignac number, because 1680181 - 2¹ = 1680179 is a prime.

It is a super-2 number, since 2×1680181² = 5646016385522, which contains 22 as substring.

Together with 1680179, 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 (1680101) 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, 840090 + 840091.

It is an arithmetic number, because the mean of its divisors is an integer number (840091).

2^1680181 is an apocalyptic number.

It is an amenable number.

1680181 is a deficient number, since it is larger than the sum of its proper divisors (1).

1680181 is an equidigital number, since it uses as much as digits as its factorization.

1680181 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 384, while the sum is 25.

The square root of 1680181 is about 1296.2179600669. The cubic root of 1680181 is about 118.8827081475.

The spelling of 1680181 in words is "one million, six hundred eighty thousand, one hundred eighty-one".