320404561 has 4 divisors (see below), whose sum is σ = 330740224. Its totient is φ = 310068900.

The previous prime is 320404531. The next prime is 320404573. The reversal of 320404561 is 165404023.

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.

It is a cyclic number.

It is not a de Polignac number, because 320404561 - 2⁵ = 320404529 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (320404531) 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, 5167785 + ... + 5167846.

It is an arithmetic number, because the mean of its divisors is an integer number (82685056).

Almost surely, 2^320404561 is an apocalyptic number.

320404561 is a gapful number since it is divisible by the number (31) formed by its first and last digit.

It is an amenable number.

320404561 is a deficient number, since it is larger than the sum of its proper divisors (10335663).

320404561 is a wasteful number, since it uses less digits than its factorization.

320404561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10335662.

The product of its (nonzero) digits is 2880, while the sum is 25.

The square root of 320404561 is about 17899.8480719809. The cubic root of 320404561 is about 684.2785029420.

Adding to 320404561 its reverse (165404023), we get a palindrome (485808584).

The spelling of 320404561 in words is "three hundred twenty million, four hundred four thousand, five hundred sixty-one".