680636681 has 4 divisors (see below), whose sum is σ = 687653652. Its totient is φ = 673619712.

The previous prime is 680636659. The next prime is 680636731. The reversal of 680636681 is 186636086.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 125798656 + 554838025 = 11216^2 + 23555^2 .

It is a cyclic number.

It is not a de Polignac number, because 680636681 - 2⁶ = 680636617 is a prime.

It is a super-2 number, since 2×680636681² = 926532583045391522, which contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (680636611) 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 in 3 ways as a sum of consecutive naturals, for example, 3508340 + ... + 3508533.

It is an arithmetic number, because the mean of its divisors is an integer number (171913413).

Almost surely, 2^680636681 is an apocalyptic number.

It is an amenable number.

680636681 is a deficient number, since it is larger than the sum of its proper divisors (7016971).

680636681 is an equidigital number, since it uses as much as digits as its factorization.

680636681 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7016970.

The product of its (nonzero) digits is 248832, while the sum is 44.

The square root of 680636681 is about 26089.0145655216. The cubic root of 680636681 is about 879.6402976360.

The spelling of 680636681 in words is "six hundred eighty million, six hundred thirty-six thousand, six hundred eighty-one".