685867849 has 2 divisors, whose sum is σ = 685867850. Its totient is φ = 685867848.

The previous prime is 685867841. The next prime is 685867879. The reversal of 685867849 is 948768586.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 428490000 + 257377849 = 20700^2 + 16043^2 .

It is a cyclic number.

It is not a de Polignac number, because 685867849 - 2³ = 685867841 is a prime.

It is not a weakly prime, because it can be changed into another prime (685867841) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 342933924 + 342933925.

It is an arithmetic number, because the mean of its divisors is an integer number (342933925).

Almost surely, 2^685867849 is an apocalyptic number.

It is an amenable number.

685867849 is a deficient number, since it is larger than the sum of its proper divisors (1).

685867849 is an equidigital number, since it uses as much as digits as its factorization.

685867849 is an evil number, because the sum of its binary digits is even.

The product of its digits is 23224320, while the sum is 61.

The square root of 685867849 is about 26189.0788115963. The cubic root of 685867849 is about 881.8880986954. Note that the first 3 decimals are identical.

The spelling of 685867849 in words is "six hundred eighty-five million, eight hundred sixty-seven thousand, eight hundred forty-nine".