720823 has 4 divisors (see below), whose sum is σ = 724680. Its totient is φ = 716968.

The previous prime is 720793. The next prime is 720829. The reversal of 720823 is 328027.

It is a happy number.

720823 is nontrivially palindromic in base 3.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 328027 = 7 ⋅46861.

It is a cyclic number.

It is not a de Polignac number, because 720823 - 2⁵ = 720791 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 720794 and 720803.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (720829) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1633 + ... + 2026.

It is an arithmetic number, because the mean of its divisors is an integer number (181170).

2⁷²⁰⁸²³ is an apocalyptic number.

720823 is a deficient number, since it is larger than the sum of its proper divisors (3857).

720823 is a wasteful number, since it uses less digits than its factorization.

720823 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3856.

The product of its (nonzero) digits is 672, while the sum is 22.

The square root of 720823 is about 849.0129563205. The cubic root of 720823 is about 89.6622318916.

Subtracting from 720823 its sum of digits (22), we obtain a square (720801 = 849²).

The spelling of 720823 in words is "seven hundred twenty thousand, eight hundred twenty-three".