3181681 has 2 divisors, whose sum is σ = 3181682. Its totient is φ = 3181680.

The previous prime is 3181679. The next prime is 3181691. The reversal of 3181681 is 1861813.

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., 1703025 + 1478656 = 1305^2 + 1216^2 .

It is a cyclic number.

It is not a de Polignac number, because 3181681 - 2¹ = 3181679 is a prime.

It is a super-2 number, since 2×3181681² = 20246187971522, which contains 22 as substring.

Together with 3181679, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (3181691) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1590840 + 1590841.

It is an arithmetic number, because the mean of its divisors is an integer number (1590841).

Almost surely, 2^3181681 is an apocalyptic number.

It is an amenable number.

3181681 is a deficient number, since it is larger than the sum of its proper divisors (1).

3181681 is an equidigital number, since it uses as much as digits as its factorization.

3181681 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1152, while the sum is 28.

The square root of 3181681 is about 1783.7267167366. The cubic root of 3181681 is about 147.0795225860.

The spelling of 3181681 in words is "three million, one hundred eighty-one thousand, six hundred eighty-one".