686885819 has 2 divisors, whose sum is σ = 686885820. Its totient is φ = 686885818.

The previous prime is 686885807. The next prime is 686885821. The reversal of 686885819 is 918588686.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-686885819 is a prime.

It is a super-2 number, since 2×686885819² = 943624256686601522, which contains 22 as substring.

Together with 686885821, it forms a pair of twin primes.

It is a Chen prime.

It is a weakly prime.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 343442909 + 343442910.

It is an arithmetic number, because the mean of its divisors is an integer number (343442910).

Almost surely, 2^686885819 is an apocalyptic number.

686885819 is a deficient number, since it is larger than the sum of its proper divisors (1).

686885819 is an equidigital number, since it uses as much as digits as its factorization.

686885819 is an evil number, because the sum of its binary digits is even.

The product of its digits is 6635520, while the sum is 59.

The square root of 686885819 is about 26208.5066152194. The cubic root of 686885819 is about 882.3241845745.

The spelling of 686885819 in words is "six hundred eighty-six million, eight hundred eighty-five thousand, eight hundred nineteen".