688449240 has 128 divisors (see below), whose sum is σ = 2368972800. Its totient is φ = 177655680.

The previous prime is 688449197. The next prime is 688449253. The reversal of 688449240 is 42944886.

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 pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 23199 + ... + 43761.

It is an arithmetic number, because the mean of its divisors is an integer number (18507600).

Almost surely, 2^688449240 is an apocalyptic number.

688449240 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 688449240, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1184486400).

688449240 is an abundant number, since it is smaller than the sum of its proper divisors (1680523560).

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

688449240 is a wasteful number, since it uses less digits than its factorization.

688449240 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 20614 (or 20604 counting only the distinct ones).

The product of its (nonzero) digits is 442368, while the sum is 45.

The square root of 688449240 is about 26238.3162569552. The cubic root of 688449240 is about 882.9930967663.

The spelling of 688449240 in words is "six hundred eighty-eight million, four hundred forty-nine thousand, two hundred forty".