320425921 has 4 divisors (see below), whose sum is σ = 320522692. Its totient is φ = 320329152.

The previous prime is 320425907. The next prime is 320425927. The reversal of 320425921 is 129524023.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 129524023 = 131 ⋅988733.

It can be written as a sum of positive squares in 2 ways, for example, as 116964225 + 203461696 = 10815^2 + 14264^2 .

It is a cyclic number.

It is not a de Polignac number, because 320425921 - 2⁹ = 320425409 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 320425921.

It is not an unprimeable number, because it can be changed into a prime (320425927) 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, 43236 + ... + 50101.

It is an arithmetic number, because the mean of its divisors is an integer number (80130673).

Almost surely, 2^320425921 is an apocalyptic number.

It is an amenable number.

320425921 is a deficient number, since it is larger than the sum of its proper divisors (96771).

320425921 is an equidigital number, since it uses as much as digits as its factorization.

320425921 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 96770.

The product of its (nonzero) digits is 4320, while the sum is 28.

The square root of 320425921 is about 17900.4447151460. Note that the first 3 decimals coincide. The cubic root of 320425921 is about 684.2937085766.

Adding to 320425921 its reverse (129524023), we get a palindrome (449949944).

The spelling of 320425921 in words is "three hundred twenty million, four hundred twenty-five thousand, nine hundred twenty-one".