406520321 has 2 divisors, whose sum is σ = 406520322. Its totient is φ = 406520320.

The previous prime is 406520311. The next prime is 406520357. The reversal of 406520321 is 123025604.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 256800625 + 149719696 = 16025^2 + 12236^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-406520321 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (406520311) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 203260160 + 203260161.

It is an arithmetic number, because the mean of its divisors is an integer number (203260161).

Almost surely, 2^406520321 is an apocalyptic number.

It is an amenable number.

406520321 is a deficient number, since it is larger than the sum of its proper divisors (1).

406520321 is an equidigital number, since it uses as much as digits as its factorization.

406520321 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1440, while the sum is 23.

The square root of 406520321 is about 20162.3490942896. The cubic root of 406520321 is about 740.7882524538.

Adding to 406520321 its reverse (123025604), we get a palindrome (529545925).

The spelling of 406520321 in words is "four hundred six million, five hundred twenty thousand, three hundred twenty-one".