681601673 has 2 divisors, whose sum is σ = 681601674. Its totient is φ = 681601672.

The previous prime is 681601667. The next prime is 681601691. The reversal of 681601673 is 376106186.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 521528569 + 160073104 = 22837^2 + 12652^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-681601673 is a prime.

It is not a weakly prime, because it can be changed into another prime (681601273) 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, 340800836 + 340800837.

It is an arithmetic number, because the mean of its divisors is an integer number (340800837).

Almost surely, 2^681601673 is an apocalyptic number.

It is an amenable number.

681601673 is a deficient number, since it is larger than the sum of its proper divisors (1).

681601673 is an equidigital number, since it uses as much as digits as its factorization.

681601673 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 36288, while the sum is 38.

The square root of 681601673 is about 26107.5022359474. The cubic root of 681601673 is about 880.0558130062.

The spelling of 681601673 in words is "six hundred eighty-one million, six hundred one thousand, six hundred seventy-three".