729281321 has 4 divisors (see below), whose sum is σ = 735735252. Its totient is φ = 722827392.

The previous prime is 729281279. The next prime is 729281339. The reversal of 729281321 is 123182927.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 170668096 + 558613225 = 13064^2 + 23635^2 .

It is a cyclic number.

It is not a de Polignac number, because 729281321 - 2¹⁴ = 729264937 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (729281381) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3226796 + ... + 3227021.

It is an arithmetic number, because the mean of its divisors is an integer number (183933813).

Almost surely, 2^729281321 is an apocalyptic number.

It is an amenable number.

729281321 is a deficient number, since it is larger than the sum of its proper divisors (6453931).

729281321 is a wasteful number, since it uses less digits than its factorization.

729281321 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6453930.

The product of its digits is 12096, while the sum is 35.

The square root of 729281321 is about 27005.2091456445. The cubic root of 729281321 is about 900.1157550702.

The spelling of 729281321 in words is "seven hundred twenty-nine million, two hundred eighty-one thousand, three hundred twenty-one".