685508839 has 2 divisors, whose sum is σ = 685508840. Its totient is φ = 685508838.

The previous prime is 685508821. The next prime is 685508849. The reversal of 685508839 is 938805586.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 685508839 - 2¹⁷ = 685377767 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (685508819) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 342754419 + 342754420.

It is an arithmetic number, because the mean of its divisors is an integer number (342754420).

Almost surely, 2^685508839 is an apocalyptic number.

685508839 is a deficient number, since it is larger than the sum of its proper divisors (1).

685508839 is an equidigital number, since it uses as much as digits as its factorization.

685508839 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 2073600, while the sum is 52.

The square root of 685508839 is about 26182.2237214489. The cubic root of 685508839 is about 881.7342002904.

The spelling of 685508839 in words is "six hundred eighty-five million, five hundred eight thousand, eight hundred thirty-nine".