720289721 has 8 divisors (see below), whose sum is σ = 725433984. Its totient is φ = 715160880.

The previous prime is 720289679. The next prime is 720289723. The reversal of 720289721 is 127982027.

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 720289721 - 2⁶ = 720289657 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (720289723) 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, 99536 + ... + 106526.

It is an arithmetic number, because the mean of its divisors is an integer number (90679248).

Almost surely, 2^720289721 is an apocalyptic number.

It is an amenable number.

720289721 is a deficient number, since it is larger than the sum of its proper divisors (5144263).

720289721 is a wasteful number, since it uses less digits than its factorization.

720289721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7711.

The product of its (nonzero) digits is 28224, while the sum is 38.

The square root of 720289721 is about 26838.2138191050. The cubic root of 720289721 is about 896.4011514369.

The spelling of 720289721 in words is "seven hundred twenty million, two hundred eighty-nine thousand, seven hundred twenty-one".