685023281 has 2 divisors, whose sum is σ = 685023282. Its totient is φ = 685023280.

The previous prime is 685023277. The next prime is 685023293. The reversal of 685023281 is 182320586.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 532871056 + 152152225 = 23084^2 + 12335^2 .

It is a cyclic number.

It is not a de Polignac number, because 685023281 - 2² = 685023277 is a prime.

It is a super-2 number, since 2×685023281² = 938513791024009922, which contains 22 as substring.

It is a Sophie Germain prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (685023271) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 342511640 + 342511641.

It is an arithmetic number, because the mean of its divisors is an integer number (342511641).

Almost surely, 2^685023281 is an apocalyptic number.

It is an amenable number.

685023281 is a deficient number, since it is larger than the sum of its proper divisors (1).

685023281 is an equidigital number, since it uses as much as digits as its factorization.

685023281 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 23040, while the sum is 35.

The square root of 685023281 is about 26172.9494134689. The cubic root of 685023281 is about 881.5259684900.

The spelling of 685023281 in words is "six hundred eighty-five million, twenty-three thousand, two hundred eighty-one".