686409099581 has 2 divisors, whose sum is σ = 686409099582. Its totient is φ = 686409099580.

The previous prime is 686409099461. The next prime is 686409099583. The reversal of 686409099581 is 185990904686.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 622252768900 + 64156330681 = 788830^2 + 253291^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-686409099581 is a prime.

It is a super-2 number, since 2×686409099581² (a number of 24 digits) contains 22 as substring.

It is a Sophie Germain prime.

Together with 686409099583, it forms a pair of twin primes.

It is a Chen prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (686409099583) 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, 343204549790 + 343204549791.

It is an arithmetic number, because the mean of its divisors is an integer number (343204549791).

Almost surely, 2^686409099581 is an apocalyptic number.

It is an amenable number.

686409099581 is a deficient number, since it is larger than the sum of its proper divisors (1).

686409099581 is an equidigital number, since it uses as much as digits as its factorization.

686409099581 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 33592320, while the sum is 65.

The spelling of 686409099581 in words is "six hundred eighty-six billion, four hundred nine million, ninety-nine thousand, five hundred eighty-one".