720920 has 32 divisors (see below), whose sum is σ = 1652400. Its totient is φ = 283008.

The previous prime is 720913. The next prime is 720931. The reversal of 720920 is 29027.

It is a Harshad number since it is a multiple of its sum of digits (20).

It is a junction number, because it is equal to n+sod(n) for n = 720892 and 720901.

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 720920.

It is an unprimeable number.

720920 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a pernicious number, because its binary representation contains a prime number (5) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2546 + ... + 2814.

2⁷²⁰⁹²⁰ is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 720920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (826200).

720920 is an abundant number, since it is smaller than the sum of its proper divisors (931480).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

720920 is a wasteful number, since it uses less digits than its factorization.

720920 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 347 (or 343 counting only the distinct ones).

The product of its (nonzero) digits is 252, while the sum is 20.

The square root of 720920 is about 849.0700795576. The cubic root of 720920 is about 89.6662536123. Note that the first 3 decimals are identical.

720920 divided by its sum of digits (20) gives a triangular number (36046 = T₂₆₈).

Adding to 720920 its reverse (29027), we get a palindrome (749947).

The spelling of 720920 in words is "seven hundred twenty thousand, nine hundred twenty".