681444780101 has 2 divisors, whose sum is σ = 681444780102. Its totient is φ = 681444780100.

The previous prime is 681444780089. The next prime is 681444780103. The reversal of 681444780101 is 101087444186.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 435824428900 + 245620351201 = 660170^2 + 495601^2 .

It is a cyclic number.

It is not a de Polignac number, because 681444780101 - 2¹⁰ = 681444779077 is a prime.

Together with 681444780103, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (681444780103) 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, 340722390050 + 340722390051.

It is an arithmetic number, because the mean of its divisors is an integer number (340722390051).

Almost surely, 2^681444780101 is an apocalyptic number.

It is an amenable number.

681444780101 is a deficient number, since it is larger than the sum of its proper divisors (1).

681444780101 is an equidigital number, since it uses as much as digits as its factorization.

681444780101 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 172032, while the sum is 44.

The spelling of 681444780101 in words is "six hundred eighty-one billion, four hundred forty-four million, seven hundred eighty thousand, one hundred one".