685012819 has 2 divisors, whose sum is σ = 685012820. Its totient is φ = 685012818.

The previous prime is 685012817. The next prime is 685012829. The reversal of 685012819 is 918210586.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 685012819 - 2¹ = 685012817 is a prime.

It is a super-2 number, since 2×685012819² = 938485124388653522, which contains 22 as substring.

Together with 685012817, 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 (685012813) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 342506409 + 342506410.

It is an arithmetic number, because the mean of its divisors is an integer number (342506410).

Almost surely, 2^685012819 is an apocalyptic number.

685012819 is a deficient number, since it is larger than the sum of its proper divisors (1).

685012819 is an equidigital number, since it uses as much as digits as its factorization.

685012819 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 34560, while the sum is 40.

The square root of 685012819 is about 26172.7495498658. The cubic root of 685012819 is about 881.5214807731.

The spelling of 685012819 in words is "six hundred eighty-five million, twelve thousand, eight hundred nineteen".