1966681 has 2 divisors, whose sum is σ = 1966682. Its totient is φ = 1966680.

The previous prime is 1966669. The next prime is 1966697. The reversal of 1966681 is 1866691.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1625625 + 341056 = 1275^2 + 584^2 .

It is a cyclic number.

It is not a de Polignac number, because 1966681 - 2¹⁵ = 1933913 is a prime.

It is a super-2 number, since 2×1966681² = 7735668311522, which contains 22 as substring.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 1966681.

It is not a weakly prime, because it can be changed into another prime (1966381) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 983340 + 983341.

It is an arithmetic number, because the mean of its divisors is an integer number (983341).

2^1966681 is an apocalyptic number.

It is an amenable number.

1966681 is a deficient number, since it is larger than the sum of its proper divisors (1).

1966681 is an equidigital number, since it uses as much as digits as its factorization.

1966681 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 15552, while the sum is 37.

The square root of 1966681 is about 1402.3840415521. The cubic root of 1966681 is about 125.2885281662.

The spelling of 1966681 in words is "one million, nine hundred sixty-six thousand, six hundred eighty-one".