161133556321 has 2 divisors, whose sum is σ = 161133556322. Its totient is φ = 161133556320.

The previous prime is 161133556303. The next prime is 161133556361. The reversal of 161133556321 is 123655331161.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 159449274721 + 1684281600 = 399311^2 + 41040^2 .

It is a cyclic number.

It is not a de Polignac number, because 161133556321 - 2¹³ = 161133548129 is a prime.

It is not a weakly prime, because it can be changed into another prime (161133556361) 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, 80566778160 + 80566778161.

It is an arithmetic number, because the mean of its divisors is an integer number (80566778161).

Almost surely, 2^161133556321 is an apocalyptic number.

It is an amenable number.

161133556321 is a deficient number, since it is larger than the sum of its proper divisors (1).

161133556321 is an equidigital number, since it uses as much as digits as its factorization.

161133556321 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 48600, while the sum is 37.

Adding to 161133556321 its reverse (123655331161), we get a palindrome (284788887482).

The spelling of 161133556321 in words is "one hundred sixty-one billion, one hundred thirty-three million, five hundred fifty-six thousand, three hundred twenty-one".