686857091 has 2 divisors, whose sum is σ = 686857092. Its totient is φ = 686857090.

The previous prime is 686857037. The next prime is 686857153. The reversal of 686857091 is 190758686.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 686857091 - 2²² = 682662787 is a prime.

It is not a weakly prime, because it can be changed into another prime (686857891) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 343428545 + 343428546.

It is an arithmetic number, because the mean of its divisors is an integer number (343428546).

Almost surely, 2^686857091 is an apocalyptic number.

686857091 is a deficient number, since it is larger than the sum of its proper divisors (1).

686857091 is an equidigital number, since it uses as much as digits as its factorization.

686857091 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 725760, while the sum is 50.

The square root of 686857091 is about 26207.9585431601. The cubic root of 686857091 is about 882.3118837613.

The spelling of 686857091 in words is "six hundred eighty-six million, eight hundred fifty-seven thousand, ninety-one".