205122221 has 8 divisors (see below), whose sum is σ = 222486264. Its totient is φ = 188346880.

The previous prime is 205122193. The next prime is 205122251. The reversal of 205122221 is 122221502.

It can be written as a sum of positive squares in 4 ways, for example, as 67059721 + 138062500 = 8189^2 + 11750^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 205122221 - 2¹⁰ = 205121197 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (17).

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 205122221.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (205122251) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 146450 + ... + 147843.

It is an arithmetic number, because the mean of its divisors is an integer number (27810783).

Almost surely, 2^205122221 is an apocalyptic number.

It is an amenable number.

205122221 is a deficient number, since it is larger than the sum of its proper divisors (17364043).

205122221 is a wasteful number, since it uses less digits than its factorization.

205122221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 294351.

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

The square root of 205122221 is about 14322.0885697583. The cubic root of 205122221 is about 589.7540112145.

Adding to 205122221 its reverse (122221502), we get a palindrome (327343723).

The spelling of 205122221 in words is "two hundred five million, one hundred twenty-two thousand, two hundred twenty-one".