685315181 has 2 divisors, whose sum is σ = 685315182. Its totient is φ = 685315180.

The previous prime is 685315157. The next prime is 685315193. The reversal of 685315181 is 181513586.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 474804100 + 210511081 = 21790^2 + 14509^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-685315181 is a prime.

It is a super-2 number, since 2×685315181² = 939313794618125522, which contains 22 as substring.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (685315121) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 342657590 + 342657591.

It is an arithmetic number, because the mean of its divisors is an integer number (342657591).

Almost surely, 2^685315181 is an apocalyptic number.

It is an amenable number.

685315181 is a deficient number, since it is larger than the sum of its proper divisors (1).

685315181 is an equidigital number, since it uses as much as digits as its factorization.

685315181 is an evil number, because the sum of its binary digits is even.

The product of its digits is 28800, while the sum is 38.

The square root of 685315181 is about 26178.5251876419. The cubic root of 685315181 is about 881.6511617483.

The spelling of 685315181 in words is "six hundred eighty-five million, three hundred fifteen thousand, one hundred eighty-one".