681486779 has 2 divisors, whose sum is σ = 681486780. Its totient is φ = 681486778.

The previous prime is 681486763. The next prime is 681486781. The reversal of 681486779 is 977684186.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 681486779 - 2⁴ = 681486763 is a prime.

Together with 681486781, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (681486719) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 340743389 + 340743390.

It is an arithmetic number, because the mean of its divisors is an integer number (340743390).

Almost surely, 2^681486779 is an apocalyptic number.

681486779 is a deficient number, since it is larger than the sum of its proper divisors (1).

681486779 is an equidigital number, since it uses as much as digits as its factorization.

681486779 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 4064256, while the sum is 56.

The square root of 681486779 is about 26105.3017412172. The cubic root of 681486779 is about 880.0063614382.

The spelling of 681486779 in words is "six hundred eighty-one million, four hundred eighty-six thousand, seven hundred seventy-nine".