205539557161 has 2 divisors, whose sum is σ = 205539557162. Its totient is φ = 205539557160.

The previous prime is 205539557147. The next prime is 205539557177. The reversal of 205539557161 is 161755935502.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 189883291536 + 15656265625 = 435756^2 + 125125^2 .

It is a cyclic number.

It is not a de Polignac number, because 205539557161 - 2⁷ = 205539557033 is a prime.

It is not a weakly prime, because it can be changed into another prime (205539557131) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 102769778580 + 102769778581.

It is an arithmetic number, because the mean of its divisors is an integer number (102769778581).

Almost surely, 2^205539557161 is an apocalyptic number.

It is an amenable number.

205539557161 is a deficient number, since it is larger than the sum of its proper divisors (1).

205539557161 is an equidigital number, since it uses as much as digits as its factorization.

205539557161 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1417500, while the sum is 49.

The spelling of 205539557161 in words is "two hundred five billion, five hundred thirty-nine million, five hundred fifty-seven thousand, one hundred sixty-one".