1606681 has 2 divisors, whose sum is σ = 1606682. Its totient is φ = 1606680.

The previous prime is 1606669. The next prime is 1606723. The reversal of 1606681 is 1866061.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1265625 + 341056 = 1125^2 + 584^2 .

It is a cyclic number.

It is not a de Polignac number, because 1606681 - 2¹⁷ = 1475609 is a prime.

It is a super-2 number, since 2×1606681² = 5162847671522, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (1606081) 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, 803340 + 803341.

It is an arithmetic number, because the mean of its divisors is an integer number (803341).

2^1606681 is an apocalyptic number.

It is an amenable number.

1606681 is a deficient number, since it is larger than the sum of its proper divisors (1).

1606681 is an equidigital number, since it uses as much as digits as its factorization.

1606681 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1728, while the sum is 28.

The square root of 1606681 is about 1267.5492100901. The cubic root of 1606681 is about 117.1232781504.

The spelling of 1606681 in words is "one million, six hundred six thousand, six hundred eighty-one".