685390819 has 16 divisors (see below), whose sum is σ = 766471680. Its totient is φ = 609068160.

The previous prime is 685390799. The next prime is 685390829. The reversal of 685390819 is 918093586.

It is a cyclic number.

It is not a de Polignac number, because 685390819 - 2¹¹ = 685388771 is a prime.

It is a super-2 number, since 2×685390819² = 939521149538981522, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (685390829) 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 in 15 ways as a sum of consecutive naturals, for example, 97042 + ... + 103864.

It is an arithmetic number, because the mean of its divisors is an integer number (47904480).

Almost surely, 2^685390819 is an apocalyptic number.

685390819 is a deficient number, since it is larger than the sum of its proper divisors (81080861).

685390819 is a wasteful number, since it uses less digits than its factorization.

685390819 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7170.

The product of its (nonzero) digits is 466560, while the sum is 49.

The square root of 685390819 is about 26179.9698051774. The cubic root of 685390819 is about 881.6835963999.

The spelling of 685390819 in words is "six hundred eighty-five million, three hundred ninety thousand, eight hundred nineteen".