681963791 has 2 divisors, whose sum is σ = 681963792. Its totient is φ = 681963790.

The previous prime is 681963769. The next prime is 681963803. The reversal of 681963791 is 197369186.

681963791 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 681963791 - 2⁶ = 681963727 is a prime.

It is a super-2 number, since 2×681963791² = 930149224470183362, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (681963691) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 340981895 + 340981896.

It is an arithmetic number, because the mean of its divisors is an integer number (340981896).

Almost surely, 2^681963791 is an apocalyptic number.

681963791 is a deficient number, since it is larger than the sum of its proper divisors (1).

681963791 is an equidigital number, since it uses as much as digits as its factorization.

681963791 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 489888, while the sum is 50.

The square root of 681963791 is about 26114.4364480645. The cubic root of 681963791 is about 880.2116359958.

The spelling of 681963791 in words is "six hundred eighty-one million, nine hundred sixty-three thousand, seven hundred ninety-one".