205221771121 has 2 divisors, whose sum is σ = 205221771122. Its totient is φ = 205221771120.

The previous prime is 205221771107. The next prime is 205221771239. The reversal of 205221771121 is 121177122502.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 196460811121 + 8760960000 = 443239^2 + 93600^2 .

It is a cyclic number.

It is not a de Polignac number, because 205221771121 - 2⁷ = 205221770993 is a prime.

It is not a weakly prime, because it can be changed into another prime (205221771421) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 102610885560 + 102610885561.

It is an arithmetic number, because the mean of its divisors is an integer number (102610885561).

Almost surely, 2^205221771121 is an apocalyptic number.

It is an amenable number.

205221771121 is a deficient number, since it is larger than the sum of its proper divisors (1).

205221771121 is an equidigital number, since it uses as much as digits as its factorization.

205221771121 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 3920, while the sum is 31.

Adding to 205221771121 its reverse (121177122502), we get a palindrome (326398893623).

The spelling of 205221771121 in words is "two hundred five billion, two hundred twenty-one million, seven hundred seventy-one thousand, one hundred twenty-one".