681488640 has 432 divisors, whose sum is σ = 2803452288. Its totient is φ = 155271168.

The previous prime is 681488629. The next prime is 681488677. The reversal of 681488640 is 46884186.

It is a tau number, because it is divible by the number of its divisors (432).

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

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 2177124 + ... + 2177436.

Almost surely, 2^681488640 is an apocalyptic number.

681488640 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 681488640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1401726144).

681488640 is an abundant number, since it is smaller than the sum of its proper divisors (2121963648).

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

681488640 is an equidigital number, since it uses as much as digits as its factorization.

681488640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 356 (or 330 counting only the distinct ones).

The product of its (nonzero) digits is 294912, while the sum is 45.

The square root of 681488640 is about 26105.3373852935. The cubic root of 681488640 is about 880.0071624761.

The spelling of 681488640 in words is "six hundred eighty-one million, four hundred eighty-eight thousand, six hundred forty".