681963851 has 2 divisors, whose sum is σ = 681963852. Its totient is φ = 681963850.

The previous prime is 681963829. The next prime is 681963853. The reversal of 681963851 is 158369186.

681963851 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 681963851 - 2¹⁸ = 681701707 is a prime.

It is a Sophie Germain prime.

Together with 681963853, it forms a pair of twin primes.

It is a Chen prime.

It is a junction number, because it is equal to n+sod(n) for n = 681963796 and 681963805.

It is not a weakly prime, because it can be changed into another prime (681963853) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 340981925 + 340981926.

It is an arithmetic number, because the mean of its divisors is an integer number (340981926).

Almost surely, 2^681963851 is an apocalyptic number.

681963851 is a deficient number, since it is larger than the sum of its proper divisors (1).

681963851 is an equidigital number, since it uses as much as digits as its factorization.

681963851 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 311040, while the sum is 47.

The square root of 681963851 is about 26114.4375968544. The cubic root of 681963851 is about 880.2116618098.

The spelling of 681963851 in words is "six hundred eighty-one million, nine hundred sixty-three thousand, eight hundred fifty-one".