730721 has 4 divisors (see below), whose sum is σ = 769200. Its totient is φ = 692244.

The previous prime is 730679. The next prime is 730727. The reversal of 730721 is 127037.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 730721 - 2¹⁸ = 468577 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 730693 and 730702.

It is not an unprimeable number, because it can be changed into a prime (730727) 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, 19211 + ... + 19248.

It is an arithmetic number, because the mean of its divisors is an integer number (192300).

2⁷³⁰⁷²¹ is an apocalyptic number.

It is an amenable number.

730721 is a deficient number, since it is larger than the sum of its proper divisors (38479).

730721 is a wasteful number, since it uses less digits than its factorization.

730721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 38478.

The product of its (nonzero) digits is 294, while the sum is 20.

The square root of 730721 is about 854.8222037360. The cubic root of 730721 is about 90.0707673860.

Adding to 730721 its reverse (127037), we get a palindrome (857758).

The spelling of 730721 in words is "seven hundred thirty thousand, seven hundred twenty-one".