686943440 has 20 divisors (see below), whose sum is σ = 1597143684. Its totient is φ = 274777344.

The previous prime is 686943409. The next prime is 686943449. The reversal of 686943440 is 44349686.

686943440 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 2 ways, for example, as 274366096 + 412577344 = 16564^2 + 20312^2 .

It is a tau number, because it is divible by the number of its divisors (20).

It is a junction number, because it is equal to n+sod(n) for n = 686943391 and 686943400.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (686943449) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4293317 + ... + 4293476.

Almost surely, 2^686943440 is an apocalyptic number.

It is an amenable number.

686943440 is an abundant number, since it is smaller than the sum of its proper divisors (910200244).

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

686943440 is a wasteful number, since it uses less digits than its factorization.

686943440 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8586806 (or 8586800 counting only the distinct ones).

The product of its (nonzero) digits is 497664, while the sum is 44.

The square root of 686943440 is about 26209.6058726567. The cubic root of 686943440 is about 882.3488558173.

The spelling of 686943440 in words is "six hundred eighty-six million, nine hundred forty-three thousand, four hundred forty".