721620717 has 8 divisors (see below), whose sum is σ = 995339040. Its totient is φ = 464491440.

The previous prime is 721620689. The next prime is 721620749. The reversal of 721620717 is 717026127.

It is a happy number.

721620717 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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

It is not a de Polignac number, because 721620717 - 2⁸ = 721620461 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (721620017) 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, 4147159 + ... + 4147332.

It is an arithmetic number, because the mean of its divisors is an integer number (124417380).

Almost surely, 2^721620717 is an apocalyptic number.

It is an amenable number.

721620717 is a deficient number, since it is larger than the sum of its proper divisors (273718323).

721620717 is a wasteful number, since it uses less digits than its factorization.

721620717 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8294523.

The product of its (nonzero) digits is 8232, while the sum is 33.

The square root of 721620717 is about 26862.9990321260. Note that the first 3 decimals coincide. The cubic root of 721620717 is about 896.9529535646.

The spelling of 721620717 in words is "seven hundred twenty-one million, six hundred twenty thousand, seven hundred seventeen".