205155451321 has 2 divisors, whose sum is σ = 205155451322. Its totient is φ = 205155451320.

The previous prime is 205155451307. The next prime is 205155451351. The reversal of 205155451321 is 123154551502.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 136282797225 + 68872654096 = 369165^2 + 262436^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-205155451321 is a prime.

It is not a weakly prime, because it can be changed into another prime (205155451351) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 102577725660 + 102577725661.

It is an arithmetic number, because the mean of its divisors is an integer number (102577725661).

Almost surely, 2^205155451321 is an apocalyptic number.

It is an amenable number.

205155451321 is a deficient number, since it is larger than the sum of its proper divisors (1).

205155451321 is an equidigital number, since it uses as much as digits as its factorization.

205155451321 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 30000, while the sum is 34.

The spelling of 205155451321 in words is "two hundred five billion, one hundred fifty-five million, four hundred fifty-one thousand, three hundred twenty-one".