686431939 has 2 divisors, whose sum is σ = 686431940. Its totient is φ = 686431938.

The previous prime is 686431937. The next prime is 686431961. The reversal of 686431939 is 939134686.

686431939 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 686431939 - 2¹ = 686431937 is a prime.

Together with 686431937, it forms a pair of twin primes.

It is a junction number, because it is equal to n+sod(n) for n = 686431892 and 686431901.

It is not a weakly prime, because it can be changed into another prime (686431931) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 343215969 + 343215970.

It is an arithmetic number, because the mean of its divisors is an integer number (343215970).

Almost surely, 2^686431939 is an apocalyptic number.

686431939 is a deficient number, since it is larger than the sum of its proper divisors (1).

686431939 is an equidigital number, since it uses as much as digits as its factorization.

686431939 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 839808, while the sum is 49.

The square root of 686431939 is about 26199.8461636705. The cubic root of 686431939 is about 882.1298012047.

The spelling of 686431939 in words is "six hundred eighty-six million, four hundred thirty-one thousand, nine hundred thirty-nine".