729840 has 40 divisors (see below), whose sum is σ = 2263248. Its totient is φ = 194560.

The previous prime is 729821. The next prime is 729851. The reversal of 729840 is 48927.

It is a tau number, because it is divible by the number of its divisors (40).

It is a Harshad number since it is a multiple of its sum of digits (30).

It is a junction number, because it is equal to n+sod(n) for n = 729798 and 729807.

It is a congruent number.

It is an unprimeable number.

729840 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1281 + ... + 1760.

2⁷²⁹⁸⁴⁰ is an apocalyptic number.

It is an amenable number.

729840 is an abundant number, since it is smaller than the sum of its proper divisors (1533408).

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

729840 is a wasteful number, since it uses less digits than its factorization.

729840 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3057 (or 3051 counting only the distinct ones).

The product of its (nonzero) digits is 4032, while the sum is 30.

The square root of 729840 is about 854.3067364829. The cubic root of 729840 is about 90.0345546326.

The spelling of 729840 in words is "seven hundred twenty-nine thousand, eight hundred forty".