681497909 has 8 divisors (see below), whose sum is σ = 717762240. Its totient is φ = 645273216.

The previous prime is 681497897. The next prime is 681497923. The reversal of 681497909 is 909794186.

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 not a de Polignac number, because 681497909 - 2¹⁶ = 681432373 is a prime.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (681497209) 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, 29432 + ... + 47214.

It is an arithmetic number, because the mean of its divisors is an integer number (89720280).

Almost surely, 2^681497909 is an apocalyptic number.

It is an amenable number.

681497909 is a deficient number, since it is larger than the sum of its proper divisors (36264331).

681497909 is a wasteful number, since it uses less digits than its factorization.

681497909 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 19819.

The product of its (nonzero) digits is 979776, while the sum is 53.

The square root of 681497909 is about 26105.5149154350. The cubic root of 681497909 is about 880.0111521486.

The spelling of 681497909 in words is "six hundred eighty-one million, four hundred ninety-seven thousand, nine hundred nine".