688705920 has 768 divisors, whose sum is σ = 3055104000. Its totient is φ = 139345920.

The previous prime is 688705883. The next prime is 688705933. The reversal of 688705920 is 29507886.

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

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 22216305 + ... + 22216335.

It is an arithmetic number, because the mean of its divisors is an integer number (3978000).

Almost surely, 2^688705920 is an apocalyptic number.

688705920 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 688705920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1527552000).

688705920 is an abundant number, since it is smaller than the sum of its proper divisors (2366398080).

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

688705920 is a wasteful number, since it uses less digits than its factorization.

688705920 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 111 (or 96 counting only the distinct ones).

The product of its (nonzero) digits is 241920, while the sum is 45.

The square root of 688705920 is about 26243.2071210818. The cubic root of 688705920 is about 883.1028209082.

The spelling of 688705920 in words is "six hundred eighty-eight million, seven hundred five thousand, nine hundred twenty".