687744640 has 192 divisors, whose sum is σ = 1846061280. Its totient is φ = 244766720.

The previous prime is 687744637. The next prime is 687744649. The reversal of 687744640 is 46447786.

It is not an unprimeable number, because it can be changed into a prime (687744649) by changing a digit.

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 23 ways as a sum of consecutive naturals, for example, 6427467 + ... + 6427573.

Almost surely, 2^687744640 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 687744640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (923030640).

687744640 is an abundant number, since it is smaller than the sum of its proper divisors (1158316640).

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

687744640 is a wasteful number, since it uses less digits than its factorization.

687744640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 231 (or 208 counting only the distinct ones).

The product of its (nonzero) digits is 903168, while the sum is 46.

The square root of 687744640 is about 26224.8858910768. The cubic root of 687744640 is about 882.6917580127.

The spelling of 687744640 in words is "six hundred eighty-seven million, seven hundred forty-four thousand, six hundred forty".