680666681 has 4 divisors (see below), whose sum is σ = 680802852. Its totient is φ = 680530512.

The previous prime is 680666677. The next prime is 680666711. The reversal of 680666681 is 186666086.

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 488012281 + 192654400 = 22091^2 + 13880^2 .

It is a cyclic number.

It is not a de Polignac number, because 680666681 - 2² = 680666677 is a prime.

It is a super-2 number, since 2×680666681² = 926614261247111522, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (680666611) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 60290 + ... + 70683.

It is an arithmetic number, because the mean of its divisors is an integer number (170200713).

Almost surely, 2^680666681 is an apocalyptic number.

It is an amenable number.

680666681 is a deficient number, since it is larger than the sum of its proper divisors (136171).

680666681 is a wasteful number, since it uses less digits than its factorization.

680666681 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 136170.

The product of its (nonzero) digits is 497664, while the sum is 47.

The square root of 680666681 is about 26089.5895138272. The cubic root of 680666681 is about 879.6532212324.

It can be divided in two parts, 68066 and 6681, that added together give a palindrome (74747).

The spelling of 680666681 in words is "six hundred eighty million, six hundred sixty-six thousand, six hundred eighty-one".