681909070209181 has 2 divisors, whose sum is σ = 681909070209182. Its totient is φ = 681909070209180.

The previous prime is 681909070209131. The next prime is 681909070209221. The reversal of 681909070209181 is 181902070909186.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 533871477824281 + 148037592384900 = 23105659^2 + 12167070^2 .

It is a cyclic number.

It is not a de Polignac number, because 681909070209181 - 2⁷ = 681909070209053 is a prime.

It is a super-2 number, since 2×681909070209181² (a number of 30 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (681909070209131) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 340954535104590 + 340954535104591.

It is an arithmetic number, because the mean of its divisors is an integer number (340954535104591).

Almost surely, 2^{681909070209181} is an apocalyptic number.

It is an amenable number.

681909070209181 is a deficient number, since it is larger than the sum of its proper divisors (1).

681909070209181 is an equidigital number, since it uses as much as digits as its factorization.

681909070209181 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 3919104, while the sum is 61.

The spelling of 681909070209181 in words is "six hundred eighty-one trillion, nine hundred nine billion, seventy million, two hundred nine thousand, one hundred eighty-one".