680971681 has 4 divisors (see below), whose sum is σ = 733354132. Its totient is φ = 628589232.

The previous prime is 680971657. The next prime is 680971691. The reversal of 680971681 is 186179086.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 186179086 = 2 ⋅93089543.

It can be written as a sum of positive squares in 2 ways, for example, as 67914081 + 613057600 = 8241^2 + 24760^2 .

It is a cyclic number.

It is not a de Polignac number, because 680971681 - 2¹⁹ = 680447393 is a prime.

It is a super-2 number, since 2×680971681² = 927444860647931522, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (680971651) 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, 26191206 + ... + 26191231.

It is an arithmetic number, because the mean of its divisors is an integer number (183338533).

Almost surely, 2^680971681 is an apocalyptic number.

It is an amenable number.

680971681 is a deficient number, since it is larger than the sum of its proper divisors (52382451).

680971681 is a wasteful number, since it uses less digits than its factorization.

680971681 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 52382450.

The product of its (nonzero) digits is 145152, while the sum is 46.

The square root of 680971681 is about 26095.4341025399. The cubic root of 680971681 is about 879.7845895789.

The spelling of 680971681 in words is "six hundred eighty million, nine hundred seventy-one thousand, six hundred eighty-one".