681921306 has 48 divisors (see below), whose sum is σ = 1706635008. Its totient is φ = 194486400.

The previous prime is 681921299. The next prime is 681921329. The reversal of 681921306 is 603129186.

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 23 ways as a sum of consecutive naturals, for example, 97930 + ... + 104661.

It is an arithmetic number, because the mean of its divisors is an integer number (35554896).

Almost surely, 2^681921306 is an apocalyptic number.

681921306 is a gapful number since it is divisible by the number (66) formed by its first and last digit.

681921306 is an abundant number, since it is smaller than the sum of its proper divisors (1024713702).

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

681921306 is a wasteful number, since it uses less digits than its factorization.

681921306 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 202627 (or 202624 counting only the distinct ones).

The product of its (nonzero) digits is 15552, while the sum is 36.

The square root of 681921306 is about 26113.6229964362. The cubic root of 681921306 is about 880.1933571329.

The spelling of 681921306 in words is "six hundred eighty-one million, nine hundred twenty-one thousand, three hundred six".