320232721 has 4 divisors (see below), whose sum is σ = 323403444. Its totient is φ = 317062000.

The previous prime is 320232713. The next prime is 320232799. The reversal of 320232721 is 127232023.

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 175271121 + 144961600 = 13239^2 + 12040^2 .

It is a cyclic number.

It is not a de Polignac number, because 320232721 - 2³ = 320232713 is a prime.

It is a Smith number, since the sum of its digits (22) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 320232692 and 320232701.

It is not an unprimeable number, because it can be changed into a prime (320233721) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1585210 + ... + 1585411.

It is an arithmetic number, because the mean of its divisors is an integer number (80850861).

Almost surely, 2^320232721 is an apocalyptic number.

It is an amenable number.

320232721 is a deficient number, since it is larger than the sum of its proper divisors (3170723).

320232721 is a wasteful number, since it uses less digits than its factorization.

320232721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3170722.

The product of its (nonzero) digits is 1008, while the sum is 22.

The square root of 320232721 is about 17895.0473874757. The cubic root of 320232721 is about 684.1561498714.

Adding to 320232721 its reverse (127232023), we get a palindrome (447464744).

The spelling of 320232721 in words is "three hundred twenty million, two hundred thirty-two thousand, seven hundred twenty-one".