720840 has 32 divisors (see below), whose sum is σ = 2162880. Its totient is φ = 192192.

The previous prime is 720829. The next prime is 720847. The reversal of 720840 is 48027.

It is a happy number.

It is a super-2 number, since 2×720840² = 1039220611200, which contains 22 as substring.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 720840.

It is not an unprimeable number, because it can be changed into a prime (720847) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2884 + ... + 3123.

It is an arithmetic number, because the mean of its divisors is an integer number (67590).

2⁷²⁰⁸⁴⁰ is an apocalyptic number.

It is an amenable number.

720840 is an abundant number, since it is smaller than the sum of its proper divisors (1442040).

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

720840 is a wasteful number, since it uses less digits than its factorization.

720840 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6021 (or 6017 counting only the distinct ones).

The product of its (nonzero) digits is 448, while the sum is 21.

The square root of 720840 is about 849.0229678872. The cubic root of 720840 is about 89.6629367553.

Adding to 720840 its reverse (48027), we get a palindrome (768867).

The spelling of 720840 in words is "seven hundred twenty thousand, eight hundred forty".