405305221 has 4 divisors (see below), whose sum is σ = 405394444. Its totient is φ = 405216000.

The previous prime is 405305209. The next prime is 405305227. The reversal of 405305221 is 122503504.

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 326344225 + 78960996 = 18065^2 + 8886^2 .

It is a cyclic number.

It is not a de Polignac number, because 405305221 - 2¹⁵ = 405272453 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 405305192 and 405305201.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (405305227) 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, 37410 + ... + 47011.

It is an arithmetic number, because the mean of its divisors is an integer number (101348611).

Almost surely, 2^405305221 is an apocalyptic number.

It is an amenable number.

405305221 is a deficient number, since it is larger than the sum of its proper divisors (89223).

405305221 is an equidigital number, since it uses as much as digits as its factorization.

405305221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 89222.

The product of its (nonzero) digits is 1200, while the sum is 22.

The square root of 405305221 is about 20132.1936459989. The cubic root of 405305221 is about 740.0494372864.

Adding to 405305221 its reverse (122503504), we get a palindrome (527808725).

The spelling of 405305221 in words is "four hundred five million, three hundred five thousand, two hundred twenty-one".