405321221 has 2 divisors, whose sum is σ = 405321222. Its totient is φ = 405321220.

The previous prime is 405321211. The next prime is 405321223. The reversal of 405321221 is 122123504.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 404572996 + 748225 = 20114^2 + 865^2 .

It is a cyclic number.

It is not a de Polignac number, because 405321221 - 2¹⁸ = 405059077 is a prime.

Together with 405321223, it forms a pair of twin primes.

It is a Chen prime.

It is a junction number, because it is equal to n+sod(n) for n = 405321193 and 405321202.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (405321223) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 202660610 + 202660611.

It is an arithmetic number, because the mean of its divisors is an integer number (202660611).

Almost surely, 2^405321221 is an apocalyptic number.

It is an amenable number.

405321221 is a deficient number, since it is larger than the sum of its proper divisors (1).

405321221 is an equidigital number, since it uses as much as digits as its factorization.

405321221 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 480, while the sum is 20.

The square root of 405321221 is about 20132.5910155648. The cubic root of 405321221 is about 740.0591753263.

Adding to 405321221 its reverse (122123504), we get a palindrome (527444725).

The spelling of 405321221 in words is "four hundred five million, three hundred twenty-one thousand, two hundred twenty-one".