681239808 has 216 divisors, whose sum is σ = 2089196928. Its totient is φ = 221294592.

The previous prime is 681239803. The next prime is 681239809. The reversal of 681239808 is 808932186.

It is a tau number, because it is divible by the number of its divisors (216).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (681239803) by changing a digit.

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 23 ways as a sum of consecutive naturals, for example, 2923660 + ... + 2923892.

It is an arithmetic number, because the mean of its divisors is an integer number (9672208).

Almost surely, 2^681239808 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 681239808, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1044598464).

681239808 is an abundant number, since it is smaller than the sum of its proper divisors (1407957120).

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

681239808 is an equidigital number, since it uses as much as digits as its factorization.

681239808 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 311 (or 285 counting only the distinct ones).

The product of its (nonzero) digits is 165888, while the sum is 45.

The square root of 681239808 is about 26100.5710282361. The cubic root of 681239808 is about 879.9000437432.

The spelling of 681239808 in words is "six hundred eighty-one million, two hundred thirty-nine thousand, eight hundred eight".