688711680 has 384 divisors, whose sum is σ = 2547417600. Its totient is φ = 176357376.

The previous prime is 688711679. The next prime is 688711687. The reversal of 688711680 is 86117886.

It is a tau number, because it is divible by the number of its divisors (384).

It is a Harshad number since it is a multiple of its sum of digits (45).

It is not an unprimeable number, because it can be changed into a prime (688711687) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 12994534 + ... + 12994586.

It is an arithmetic number, because the mean of its divisors is an integer number (6633900).

Almost surely, 2^688711680 is an apocalyptic number.

688711680 is a gapful number since it is divisible by the number (60) 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 688711680, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1273708800).

688711680 is an abundant number, since it is smaller than the sum of its proper divisors (1858705920).

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

688711680 is a wasteful number, since it uses less digits than its factorization.

688711680 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 136 (or 110 counting only the distinct ones).

The product of its (nonzero) digits is 129024, while the sum is 45.

The square root of 688711680 is about 26243.3168635369. The cubic root of 688711680 is about 883.1052828483.

The spelling of 688711680 in words is "six hundred eighty-eight million, seven hundred eleven thousand, six hundred eighty".