681668245 has 16 divisors (see below), whose sum is σ = 834944112. Its totient is φ = 534077440.

The previous prime is 681668237. The next prime is 681668257. The reversal of 681668245 is 542866186.

It can be written as a sum of positive squares in 8 ways, for example, as 136258929 + 545409316 = 11673^2 + 23354^2 .

It is not a de Polignac number, because 681668245 - 2³ = 681668237 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 681668195 and 681668204.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 167859 + ... + 171871.

It is an arithmetic number, because the mean of its divisors is an integer number (52184007).

Almost surely, 2^681668245 is an apocalyptic number.

It is an amenable number.

681668245 is a deficient number, since it is larger than the sum of its proper divisors (153275867).

681668245 is a wasteful number, since it uses less digits than its factorization.

681668245 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4712.

The product of its digits is 552960, while the sum is 46.

The square root of 681668245 is about 26108.7771640113. Note that the first 3 decimals coincide. The cubic root of 681668245 is about 880.0844637420.

The spelling of 681668245 in words is "six hundred eighty-one million, six hundred sixty-eight thousand, two hundred forty-five".