726721 has 4 divisors (see below), whose sum is σ = 736000. Its totient is φ = 717444.

The previous prime is 726707. The next prime is 726751. The reversal of 726721 is 127627.

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 726721 - 2⁵ = 726689 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (726701) 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, 4521 + ... + 4678.

It is an arithmetic number, because the mean of its divisors is an integer number (184000).

2⁷²⁶⁷²¹ is an apocalyptic number.

It is an amenable number.

726721 is a deficient number, since it is larger than the sum of its proper divisors (9279).

726721 is an equidigital number, since it uses as much as digits as its factorization.

726721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9278.

The product of its digits is 1176, while the sum is 25.

The square root of 726721 is about 852.4793252625. The cubic root of 726721 is about 89.9061160904.

The spelling of 726721 in words is "seven hundred twenty-six thousand, seven hundred twenty-one".