686729664 has 196 divisors, whose sum is σ = 2098822320. Its totient is φ = 222704640.

The previous prime is 686729663. The next prime is 686729669. The reversal of 686729664 is 466927686.

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

It is a self number, because there is not a number n which added to its sum of digits gives 686729664.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (686729663) by changing a digit.

It is a polite number, since it can be written in 27 ways as a sum of consecutive naturals, for example, 1912717 + ... + 1913075.

Almost surely, 2^686729664 is an apocalyptic number.

686729664 is a gapful number since it is divisible by the number (64) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 686729664, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1049411160).

686729664 is an abundant number, since it is smaller than the sum of its proper divisors (1412092656).

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

686729664 is an equidigital number, since it uses as much as digits as its factorization.

686729664 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 430 (or 405 counting only the distinct ones).

The product of its digits is 5225472, while the sum is 54.

The square root of 686729664 is about 26205.5273558843. The cubic root of 686729664 is about 882.2573176750.

The spelling of 686729664 in words is "six hundred eighty-six million, seven hundred twenty-nine thousand, six hundred sixty-four".