721668959 has 8 divisors (see below), whose sum is σ = 788665680. Its totient is φ = 654904000.

The previous prime is 721668949. The next prime is 721669007. The reversal of 721668959 is 959866127.

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-721668959 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 721668959.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (721668929) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 51392 + ... + 63909.

It is an arithmetic number, because the mean of its divisors is an integer number (98583210).

Almost surely, 2^721668959 is an apocalyptic number.

721668959 is a deficient number, since it is larger than the sum of its proper divisors (66996721).

721668959 is a wasteful number, since it uses less digits than its factorization.

721668959 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 115881.

The product of its digits is 1632960, while the sum is 53.

The square root of 721668959 is about 26863.8969436677. The cubic root of 721668959 is about 896.9729409066.

The spelling of 721668959 in words is "seven hundred twenty-one million, six hundred sixty-eight thousand, nine hundred fifty-nine".