720686317 has 8 divisors (see below), whose sum is σ = 777307160. Its totient is φ = 664234560.

The previous prime is 720686299. The next prime is 720686353. The reversal of 720686317 is 713686027.

It can be written as a sum of positive squares in 4 ways, for example, as 14243076 + 706443241 = 3774^2 + 26579^2 .

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-720686317 is a prime.

It is a super-2 number, since 2×720686317² = 1038777535022048978, which contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 720686317.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (720683317) 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, 33342 + ... + 50527.

It is an arithmetic number, because the mean of its divisors is an integer number (97163395).

Almost surely, 2^720686317 is an apocalyptic number.

It is an amenable number.

720686317 is a deficient number, since it is larger than the sum of its proper divisors (56620843).

720686317 is a wasteful number, since it uses less digits than its factorization.

720686317 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 84543.

The product of its (nonzero) digits is 84672, while the sum is 40.

The square root of 720686317 is about 26845.6014460470. The cubic root of 720686317 is about 896.5656426002.

The spelling of 720686317 in words is "seven hundred twenty million, six hundred eighty-six thousand, three hundred seventeen".