686698139 has 2 divisors, whose sum is σ = 686698140. Its totient is φ = 686698138.

The previous prime is 686698127. The next prime is 686698141. The reversal of 686698139 is 931896686.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 686698139 - 2⁴ = 686698123 is a prime.

Together with 686698141, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (686698039) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 343349069 + 343349070.

It is an arithmetic number, because the mean of its divisors is an integer number (343349070).

Almost surely, 2^686698139 is an apocalyptic number.

686698139 is a deficient number, since it is larger than the sum of its proper divisors (1).

686698139 is an equidigital number, since it uses as much as digits as its factorization.

686698139 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 3359232, while the sum is 56.

The square root of 686698139 is about 26204.9258537398. The cubic root of 686698139 is about 882.2438171720.

The spelling of 686698139 in words is "six hundred eighty-six million, six hundred ninety-eight thousand, one hundred thirty-nine".