681791009 has 8 divisors (see below), whose sum is σ = 698810112. Its totient is φ = 664790560.

The previous prime is 681790973. The next prime is 681791017. The reversal of 681791009 is 900197186.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-681791009 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (41).

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (681791609) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 95912 + ... + 102774.

It is an arithmetic number, because the mean of its divisors is an integer number (87351264).

Almost surely, 2^681791009 is an apocalyptic number.

It is an amenable number.

681791009 is a deficient number, since it is larger than the sum of its proper divisors (17019103).

681791009 is a wasteful number, since it uses less digits than its factorization.

681791009 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9327.

The product of its (nonzero) digits is 27216, while the sum is 41.

The square root of 681791009 is about 26111.1280683160. The cubic root of 681791009 is about 880.1372930592.

The spelling of 681791009 in words is "six hundred eighty-one million, seven hundred ninety-one thousand, nine".