685369591 has 2 divisors, whose sum is σ = 685369592. Its totient is φ = 685369590.

The previous prime is 685369579. The next prime is 685369639. The reversal of 685369591 is 195963586.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-685369591 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (685369541) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 342684795 + 342684796.

It is an arithmetic number, because the mean of its divisors is an integer number (342684796).

Almost surely, 2^685369591 is an apocalyptic number.

685369591 is a deficient number, since it is larger than the sum of its proper divisors (1).

685369591 is an equidigital number, since it uses as much as digits as its factorization.

685369591 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1749600, while the sum is 52.

The square root of 685369591 is about 26179.5643775828. The cubic root of 685369591 is about 881.6744937721.

The spelling of 685369591 in words is "six hundred eighty-five million, three hundred sixty-nine thousand, five hundred ninety-one".