688642240 has 224 divisors, whose sum is σ = 1958644800. Its totient is φ = 227328000.

The previous prime is 688642231. The next prime is 688642247. The reversal of 688642240 is 42246886.

It is a Harshad number since it is a multiple of its sum of digits (40).

It is a junction number, because it is equal to n+sod(n) for n = 688642193 and 688642202.

It is not an unprimeable number, because it can be changed into a prime (688642247) 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, 4621686 + ... + 4621834.

It is an arithmetic number, because the mean of its divisors is an integer number (8743950).

Almost surely, 2^688642240 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 688642240, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (979322400).

688642240 is an abundant number, since it is smaller than the sum of its proper divisors (1270002560).

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

688642240 is a wasteful number, since it uses less digits than its factorization.

688642240 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 291 (or 281 counting only the distinct ones).

The product of its (nonzero) digits is 147456, while the sum is 40.

The square root of 688642240 is about 26241.9938266893. The cubic root of 688642240 is about 883.0756018784.

The spelling of 688642240 in words is "six hundred eighty-eight million, six hundred forty-two thousand, two hundred forty".