161220181273 has 2 divisors, whose sum is σ = 161220181274. Its totient is φ = 161220181272.

The previous prime is 161220181223. The next prime is 161220181333. The reversal of 161220181273 is 372181022161.

161220181273 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 152512118784 + 8708062489 = 390528^2 + 93317^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-161220181273 is a prime.

It is not a weakly prime, because it can be changed into another prime (161220181223) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 80610090636 + 80610090637.

It is an arithmetic number, because the mean of its divisors is an integer number (80610090637).

Almost surely, 2^161220181273 is an apocalyptic number.

It is an amenable number.

161220181273 is a deficient number, since it is larger than the sum of its proper divisors (1).

161220181273 is an equidigital number, since it uses as much as digits as its factorization.

161220181273 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 8064, while the sum is 34.

The spelling of 161220181273 in words is "one hundred sixty-one billion, two hundred twenty million, one hundred eighty-one thousand, two hundred seventy-three".