205122121 has 4 divisors (see below), whose sum is σ = 206307972. Its totient is φ = 203936272.

The previous prime is 205122107. The next prime is 205122143. The reversal of 205122121 is 121221502.

It is a happy number.

205122121 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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 87703225 + 117418896 = 9365^2 + 10836^2 .

It is a cyclic number.

It is not a de Polignac number, because 205122121 - 2⁷ = 205121993 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 205122095 and 205122104.

It is not an unprimeable number, because it can be changed into a prime (205122721) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 592666 + ... + 593011.

It is an arithmetic number, because the mean of its divisors is an integer number (51576993).

Almost surely, 2^205122121 is an apocalyptic number.

It is an amenable number.

205122121 is a deficient number, since it is larger than the sum of its proper divisors (1185851).

205122121 is a wasteful number, since it uses less digits than its factorization.

205122121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1185850.

The product of its (nonzero) digits is 80, while the sum is 16.

The square root of 205122121 is about 14322.0850786469. The cubic root of 205122121 is about 589.7539153767.

Adding to 205122121 its reverse (121221502), we get a palindrome (326343623).

The spelling of 205122121 in words is "two hundred five million, one hundred twenty-two thousand, one hundred twenty-one".