686809040 has 40 divisors (see below), whose sum is σ = 1635785928. Its totient is φ = 268021760.

The previous prime is 686808973. The next prime is 686809051. The reversal of 686809040 is 40908686.

It can be written as a sum of positive squares in 4 ways, for example, as 7268416 + 679540624 = 2696^2 + 26068^2 .

It is a tau number, because it is divible by the number of its divisors (40).

It is a Harshad number since it is a multiple of its sum of digits (41).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 101417 + ... + 107976.

Almost surely, 2^686809040 is an apocalyptic number.

It is an amenable number.

686809040 is an abundant number, since it is smaller than the sum of its proper divisors (948976888).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

686809040 is a wasteful number, since it uses less digits than its factorization.

686809040 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 209447 (or 209441 counting only the distinct ones).

The product of its (nonzero) digits is 82944, while the sum is 41.

The square root of 686809040 is about 26207.0418017753. The cubic root of 686809040 is about 882.2913084201.

The spelling of 686809040 in words is "six hundred eighty-six million, eight hundred nine thousand, forty".