65557320161 has 2 divisors, whose sum is σ = 65557320162. Its totient is φ = 65557320160.

The previous prime is 65557320083. The next prime is 65557320209. The reversal of 65557320161 is 16102375556.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 33173158225 + 32384161936 = 182135^2 + 179956^2 .

It is a cyclic number.

It is not a de Polignac number, because 65557320161 - 2¹⁰ = 65557319137 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (65557320761) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 32778660080 + 32778660081.

It is an arithmetic number, because the mean of its divisors is an integer number (32778660081).

Almost surely, 2^65557320161 is an apocalyptic number.

It is an amenable number.

65557320161 is a deficient number, since it is larger than the sum of its proper divisors (1).

65557320161 is an equidigital number, since it uses as much as digits as its factorization.

65557320161 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 189000, while the sum is 41.

The spelling of 65557320161 in words is "sixty-five billion, five hundred fifty-seven million, three hundred twenty thousand, one hundred sixty-one".