686923109 has 2 divisors, whose sum is σ = 686923110. Its totient is φ = 686923108.

The previous prime is 686923067. The next prime is 686923117. The reversal of 686923109 is 901329686.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 680688100 + 6235009 = 26090^2 + 2497^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-686923109 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 686923109.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (686923309) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 343461554 + 343461555.

It is an arithmetic number, because the mean of its divisors is an integer number (343461555).

Almost surely, 2^686923109 is an apocalyptic number.

It is an amenable number.

686923109 is a deficient number, since it is larger than the sum of its proper divisors (1).

686923109 is an equidigital number, since it uses as much as digits as its factorization.

686923109 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 139968, while the sum is 44.

The square root of 686923109 is about 26209.2180158050. The cubic root of 686923109 is about 882.3401509708.

The spelling of 686923109 in words is "six hundred eighty-six million, nine hundred twenty-three thousand, one hundred nine".