685172669 has 2 divisors, whose sum is σ = 685172670. Its totient is φ = 685172668.

The previous prime is 685172639. The next prime is 685172687. The reversal of 685172669 is 966271586.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 655872100 + 29300569 = 25610^2 + 5413^2 .

It is a cyclic number.

It is not a de Polignac number, because 685172669 - 2¹² = 685168573 is a prime.

It is a super-2 number, since 2×685172669² = 938923172689167122, 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 (685172639) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 342586334 + 342586335.

It is an arithmetic number, because the mean of its divisors is an integer number (342586335).

Almost surely, 2^685172669 is an apocalyptic number.

It is an amenable number.

685172669 is a deficient number, since it is larger than the sum of its proper divisors (1).

685172669 is an equidigital number, since it uses as much as digits as its factorization.

685172669 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1088640, while the sum is 50.

The square root of 685172669 is about 26175.8031204393. The cubic root of 685172669 is about 881.5900440883.

The spelling of 685172669 in words is "six hundred eighty-five million, one hundred seventy-two thousand, six hundred sixty-nine".