728651321 has 4 divisors (see below), whose sum is σ = 728740752. Its totient is φ = 728561892.

The previous prime is 728651309. The next prime is 728651327. The reversal of 728651321 is 123156827.

It is a happy number.

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, and also an emirpimes, since its reverse is a distinct semiprime: 123156827 = 9533 ⋅12919.

It is a cyclic number.

It is not a de Polignac number, because 728651321 - 2⁶ = 728651257 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (728651327) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 31115 + ... + 49248.

It is an arithmetic number, because the mean of its divisors is an integer number (182185188).

Almost surely, 2^728651321 is an apocalyptic number.

It is an amenable number.

728651321 is a deficient number, since it is larger than the sum of its proper divisors (89431).

728651321 is an equidigital number, since it uses as much as digits as its factorization.

728651321 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 89430.

The product of its digits is 20160, while the sum is 35.

The square root of 728651321 is about 26993.5422092026. The cubic root of 728651321 is about 899.8564878166.

The spelling of 728651321 in words is "seven hundred twenty-eight million, six hundred fifty-one thousand, three hundred twenty-one".