688849920 has 440 divisors, whose sum is σ = 2710686528. Its totient is φ = 165888000.

The previous prime is 688849919. The next prime is 688849927. The reversal of 688849920 is 29948886.

It is a tau number, because it is divible by the number of its divisors (440).

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

It is not an unprimeable number, because it can be changed into a prime (688849927) by changing a digit.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 4561845 + ... + 4561995.

Almost surely, 2^688849920 is an apocalyptic number.

688849920 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 688849920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1355343264).

688849920 is an abundant number, since it is smaller than the sum of its proper divisors (2021836608).

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

688849920 is a wasteful number, since it uses less digits than its factorization.

688849920 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 199 (or 172 counting only the distinct ones).

The product of its (nonzero) digits is 1990656, while the sum is 54.

The square root of 688849920 is about 26245.9505447983. The cubic root of 688849920 is about 883.1643652919.

Subtracting from 688849920 its product of nonzero digits (1990656), we obtain a square (686859264 = 26208²).

The spelling of 688849920 in words is "six hundred eighty-eight million, eight hundred forty-nine thousand, nine hundred twenty".