681543909 has 16 divisors (see below), whose sum is σ = 1012521600. Its totient is φ = 453090528.

The previous prime is 681543881. The next prime is 681543917. The reversal of 681543909 is 909345186.

It is a happy number.

681543909 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 681543909 - 2¹² = 681539813 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (681543979) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 25464 + ... + 44849.

It is an arithmetic number, because the mean of its divisors is an integer number (63282600).

Almost surely, 2^681543909 is an apocalyptic number.

It is an amenable number.

681543909 is a deficient number, since it is larger than the sum of its proper divisors (330977691).

681543909 is a wasteful number, since it uses less digits than its factorization.

681543909 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 70681 (or 70675 counting only the distinct ones).

The product of its (nonzero) digits is 233280, while the sum is 45.

The square root of 681543909 is about 26106.3959404587. The cubic root of 681543909 is about 880.0309514768.

The spelling of 681543909 in words is "six hundred eighty-one million, five hundred forty-three thousand, nine hundred nine".