686129749 has 2 divisors, whose sum is σ = 686129750. Its totient is φ = 686129748.

The previous prime is 686129737. The next prime is 686129753. The reversal of 686129749 is 947921686.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 654848100 + 31281649 = 25590^2 + 5593^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-686129749 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 686129696 and 686129705.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (686129849) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 343064874 + 343064875.

It is an arithmetic number, because the mean of its divisors is an integer number (343064875).

Almost surely, 2^686129749 is an apocalyptic number.

It is an amenable number.

686129749 is a deficient number, since it is larger than the sum of its proper divisors (1).

686129749 is an equidigital number, since it uses as much as digits as its factorization.

686129749 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1306368, while the sum is 52.

The square root of 686129749 is about 26194.0785102282. The cubic root of 686129749 is about 882.0003346512. Note that the first 3 decimals are identical.

The spelling of 686129749 in words is "six hundred eighty-six million, one hundred twenty-nine thousand, seven hundred forty-nine".