685312987 has 2 divisors, whose sum is σ = 685312988. Its totient is φ = 685312986.

The previous prime is 685312981. The next prime is 685313003. The reversal of 685312987 is 789213586.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-685312987 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 685312987.

It is not a weakly prime, because it can be changed into another prime (685312981) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 342656493 + 342656494.

It is an arithmetic number, because the mean of its divisors is an integer number (342656494).

Almost surely, 2^685312987 is an apocalyptic number.

685312987 is a deficient number, since it is larger than the sum of its proper divisors (1).

685312987 is an equidigital number, since it uses as much as digits as its factorization.

685312987 is an evil number, because the sum of its binary digits is even.

The product of its digits is 725760, while the sum is 49.

The square root of 685312987 is about 26178.4832830323. The cubic root of 685312987 is about 881.6502208942.

The spelling of 685312987 in words is "six hundred eighty-five million, three hundred twelve thousand, nine hundred eighty-seven".