720817 has 8 divisors (see below), whose sum is σ = 772200. Its totient is φ = 670464.

The previous prime is 720793. The next prime is 720829. The reversal of 720817 is 718027.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 167281 + 553536 = 409^2 + 744^2 .

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-720817 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 720791 and 720800.

It is not an unprimeable number, because it can be changed into a prime (720847) 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, 1659 + ... + 2047.

It is an arithmetic number, because the mean of its divisors is an integer number (96525).

2⁷²⁰⁸¹⁷ is an apocalyptic number.

It is an amenable number.

720817 is a deficient number, since it is larger than the sum of its proper divisors (51383).

720817 is a wasteful number, since it uses less digits than its factorization.

720817 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 515.

The product of its (nonzero) digits is 784, while the sum is 25.

The square root of 720817 is about 849.0094227981. The cubic root of 720817 is about 89.6619831135.

It can be divided in two parts, 7208 and 17, that added together give a square (7225 = 85²).

The spelling of 720817 in words is "seven hundred twenty thousand, eight hundred seventeen".