729021 has 8 divisors (see below), whose sum is σ = 995904. Its totient is φ = 474080.

The previous prime is 729019. The next prime is 729023. The reversal of 729021 is 120927.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (729019) and next prime (729023).

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 729021 - 2¹ = 729019 is a prime.

729021 is a lucky number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (729023) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2841 + ... + 3086.

It is an arithmetic number, because the mean of its divisors is an integer number (124488).

2⁷²⁹⁰²¹ is an apocalyptic number.

It is an amenable number.

729021 is a deficient number, since it is larger than the sum of its proper divisors (266883).

729021 is a wasteful number, since it uses less digits than its factorization.

729021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5971.

The product of its (nonzero) digits is 252, while the sum is 21.

The square root of 729021 is about 853.8272659034. The cubic root of 729021 is about 90.0008641892. Note that the first 3 decimals are identical.

Subtracting from 729021 its sum of digits (21), we obtain a cube (729000 = 90³).

Adding to 729021 its reverse (120927), we get a palindrome (849948).

The spelling of 729021 in words is "seven hundred twenty-nine thousand, twenty-one".