686645478 has 32 divisors (see below), whose sum is σ = 1528266720. Its totient is φ = 228523680.

The previous prime is 686645459. The next prime is 686645489. The reversal of 686645478 is 874546686.

686645478 is a `hidden beast` number, since 68 + 66 + 454 + 78 = 666.

686645478 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a Harshad number since it is a multiple of its sum of digits (54).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 26076 + ... + 45312.

It is an arithmetic number, because the mean of its divisors is an integer number (47758335).

Almost surely, 2^686645478 is an apocalyptic number.

686645478 is an abundant number, since it is smaller than the sum of its proper divisors (841621242).

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

686645478 is a wasteful number, since it uses less digits than its factorization.

686645478 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 19909 (or 19903 counting only the distinct ones).

The product of its digits is 7741440, while the sum is 54.

The square root of 686645478 is about 26203.9210424700. The cubic root of 686645478 is about 882.2212643080.

The spelling of 686645478 in words is "six hundred eighty-six million, six hundred forty-five thousand, four hundred seventy-eight".