686128429 has 24 divisors (see below), whose sum is σ = 833173560. Its totient is φ = 562673664.

The previous prime is 686128403. The next prime is 686128439. The reversal of 686128429 is 924821686.

It can be written as a sum of positive squares in 4 ways, for example, as 1102500 + 685025929 = 1050^2 + 26173^2 .

It is not a de Polignac number, because 686128429 - 2⁵ = 686128397 is a prime.

It is a Smith number, since the sum of its digits (46) coincides with the sum of the digits of its prime factors.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (686128439) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 158437 + ... + 162709.

It is an arithmetic number, because the mean of its divisors is an integer number (34715565).

Almost surely, 2^686128429 is an apocalyptic number.

It is an amenable number.

686128429 is a deficient number, since it is larger than the sum of its proper divisors (147045131).

686128429 is a wasteful number, since it uses less digits than its factorization.

686128429 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4429 (or 4422 counting only the distinct ones).

The product of its digits is 331776, while the sum is 46.

The square root of 686128429 is about 26194.0533136817. The cubic root of 686128429 is about 881.9997690434. Note that the first 3 decimals are identical.

The spelling of 686128429 in words is "six hundred eighty-six million, one hundred twenty-eight thousand, four hundred twenty-nine".