681598649 has 8 divisors (see below), whose sum is σ = 691532160. Its totient is φ = 671697936.

The previous prime is 681598597. The next prime is 681598657. The reversal of 681598649 is 946895186.

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-681598649 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 681598594 and 681598603.

It is not an unprimeable number, because it can be changed into a prime (681598249) 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, 35327 + ... + 51099.

It is an arithmetic number, because the mean of its divisors is an integer number (86441520).

Almost surely, 2^681598649 is an apocalyptic number.

It is an amenable number.

681598649 is a deficient number, since it is larger than the sum of its proper divisors (9933511).

681598649 is a wasteful number, since it uses less digits than its factorization.

681598649 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 16399.

The product of its digits is 3732480, while the sum is 56.

The square root of 681598649 is about 26107.4443214957. Note that the first 3 decimals coincide. The cubic root of 681598649 is about 880.0545115165.

The spelling of 681598649 in words is "six hundred eighty-one million, five hundred ninety-eight thousand, six hundred forty-nine".