205401221 has 2 divisors, whose sum is σ = 205401222. Its totient is φ = 205401220.

The previous prime is 205401211. The next prime is 205401263. The reversal of 205401221 is 122104502.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 150062500 + 55338721 = 12250^2 + 7439^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-205401221 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 205401221.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (205401211) 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 as a sum of consecutive naturals, namely, 102700610 + 102700611.

It is an arithmetic number, because the mean of its divisors is an integer number (102700611).

Almost surely, 2^205401221 is an apocalyptic number.

It is an amenable number.

205401221 is a deficient number, since it is larger than the sum of its proper divisors (1).

205401221 is an equidigital number, since it uses as much as digits as its factorization.

205401221 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 160, while the sum is 17.

The square root of 205401221 is about 14331.8254594451. The cubic root of 205401221 is about 590.0212776009.

Adding to 205401221 its reverse (122104502), we get a palindrome (327505723).

The spelling of 205401221 in words is "two hundred five million, four hundred one thousand, two hundred twenty-one".