688440306240 has 448 divisors, whose sum is σ = 2515935755520. Its totient is φ = 179306846208.

The previous prime is 688440306233. The next prime is 688440306287. The reversal of 688440306240 is 42603044886.

688440306240 is a `hidden beast` number, since 6 + 88 + 440 + 30 + 62 + 40 = 666.

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

It is an unprimeable number.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 30081682 + ... + 30104558.

Almost surely, 2^688440306240 is an apocalyptic number.

688440306240 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 688440306240, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1257967877760).

688440306240 is an abundant number, since it is smaller than the sum of its proper divisors (1827495449280).

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

688440306240 is an equidigital number, since it uses as much as digits as its factorization.

688440306240 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 22958 (or 22930 counting only the distinct ones).

The product of its (nonzero) digits is 884736, while the sum is 45.

The spelling of 688440306240 in words is "six hundred eighty-eight billion, four hundred forty million, three hundred six thousand, two hundred forty".