681481414661 has 2 divisors, whose sum is σ = 681481414662. Its totient is φ = 681481414660.

The previous prime is 681481414643. The next prime is 681481414729. The reversal of 681481414661 is 166414184186.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 460857688225 + 220623726436 = 678865^2 + 469706^2 .

It is a cyclic number.

It is not a de Polignac number, because 681481414661 - 2²² = 681477220357 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (681481414631) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 340740707330 + 340740707331.

It is an arithmetic number, because the mean of its divisors is an integer number (340740707331).

Almost surely, 2^681481414661 is an apocalyptic number.

It is an amenable number.

681481414661 is a deficient number, since it is larger than the sum of its proper divisors (1).

681481414661 is an equidigital number, since it uses as much as digits as its factorization.

681481414661 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 884736, while the sum is 50.

The spelling of 681481414661 in words is "six hundred eighty-one billion, four hundred eighty-one million, four hundred fourteen thousand, six hundred sixty-one".