688647968 has 72 divisors (see below), whose sum is σ = 1501282188. Its totient is φ = 309850112.

The previous prime is 688647943. The next prime is 688648021. The reversal of 688647968 is 869746886.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 668325904 + 20322064 = 25852^2 + 4508^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 688647968.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 286580 + ... + 288972.

Almost surely, 2^688647968 is an apocalyptic number.

688647968 is a gapful number since it is divisible by the number (68) 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 688647968, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (750641094).

688647968 is an abundant number, since it is smaller than the sum of its proper divisors (812634220).

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

688647968 is a wasteful number, since it uses less digits than its factorization.

688647968 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2466 (or 2435 counting only the distinct ones).

The product of its digits is 27869184, while the sum is 62.

The square root of 688647968 is about 26242.1029645111. The cubic root of 688647968 is about 883.0780502919.

The spelling of 688647968 in words is "six hundred eighty-eight million, six hundred forty-seven thousand, nine hundred sixty-eight".