405306221 has 2 divisors, whose sum is σ = 405306222. Its totient is φ = 405306220.

The previous prime is 405306217. The next prime is 405306227. The reversal of 405306221 is 122603504.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 271788196 + 133518025 = 16486^2 + 11555^2 .

It is a cyclic number.

It is not a de Polignac number, because 405306221 - 2² = 405306217 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (405306227) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 202653110 + 202653111.

It is an arithmetic number, because the mean of its divisors is an integer number (202653111).

Almost surely, 2^405306221 is an apocalyptic number.

It is an amenable number.

405306221 is a deficient number, since it is larger than the sum of its proper divisors (1).

405306221 is an equidigital number, since it uses as much as digits as its factorization.

405306221 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 405306221 is about 20132.2184818266. The cubic root of 405306221 is about 740.0500459214.

Adding to 405306221 its reverse (122603504), we get a palindrome (527909725).

The spelling of 405306221 in words is "four hundred five million, three hundred six thousand, two hundred twenty-one".