161100217121 has 2 divisors, whose sum is σ = 161100217122. Its totient is φ = 161100217120.

The previous prime is 161100217081. The next prime is 161100217177. The reversal of 161100217121 is 121712001161.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 126334750096 + 34765467025 = 355436^2 + 186455^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-161100217121 is a prime.

It is not a weakly prime, because it can be changed into another prime (161100217021) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 80550108560 + 80550108561.

It is an arithmetic number, because the mean of its divisors is an integer number (80550108561).

Almost surely, 2^161100217121 is an apocalyptic number.

It is an amenable number.

161100217121 is a deficient number, since it is larger than the sum of its proper divisors (1).

161100217121 is an equidigital number, since it uses as much as digits as its factorization.

161100217121 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 168, while the sum is 23.

Adding to 161100217121 its reverse (121712001161), we get a palindrome (282812218282).

The spelling of 161100217121 in words is "one hundred sixty-one billion, one hundred million, two hundred seventeen thousand, one hundred twenty-one".