685738442197 has 2 divisors, whose sum is σ = 685738442198. Its totient is φ = 685738442196.

The previous prime is 685738442173. The next prime is 685738442261. The reversal of 685738442197 is 791244837586.

It is an a-pointer prime, because the next prime (685738442261) can be obtained adding 685738442197 to its sum of digits (64).

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 638615149956 + 47123292241 = 799134^2 + 217079^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-685738442197 is a prime.

It is a super-2 number, since 2×685738442197² (a number of 24 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (685738442167) 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, 342869221098 + 342869221099.

It is an arithmetic number, because the mean of its divisors is an integer number (342869221099).

Almost surely, 2^685738442197 is an apocalyptic number.

It is an amenable number.

685738442197 is a deficient number, since it is larger than the sum of its proper divisors (1).

685738442197 is an equidigital number, since it uses as much as digits as its factorization.

685738442197 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 81285120, while the sum is 64.

The spelling of 685738442197 in words is "six hundred eighty-five billion, seven hundred thirty-eight million, four hundred forty-two thousand, one hundred ninety-seven".