685738442261 has 2 divisors, whose sum is σ = 685738442262. Its totient is φ = 685738442260.

The previous prime is 685738442197. The next prime is 685738442329. The reversal of 685738442261 is 162244837586.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 534499899025 + 151238543236 = 731095^2 + 388894^2 .

It is a cyclic number.

It is not a de Polignac number, because 685738442261 - 2⁶ = 685738442197 is a prime.

It is a super-2 number, since 2×685738442261² (a number of 24 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 685738442197 and 685738442206.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (685738448261) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 342869221130 + 342869221131.

It is an arithmetic number, because the mean of its divisors is an integer number (342869221131).

Almost surely, 2^685738442261 is an apocalyptic number.

It is an amenable number.

685738442261 is a deficient number, since it is larger than the sum of its proper divisors (1).

685738442261 is an equidigital number, since it uses as much as digits as its factorization.

685738442261 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 15482880, while the sum is 56.

The spelling of 685738442261 in words is "six hundred eighty-five billion, seven hundred thirty-eight million, four hundred forty-two thousand, two hundred sixty-one".