161829520681 has 2 divisors, whose sum is σ = 161829520682. Its totient is φ = 161829520680.

The previous prime is 161829520661. The next prime is 161829520703. The reversal of 161829520681 is 186025928161.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 95582997225 + 66246523456 = 309165^2 + 257384^2 .

It is an emirp because it is prime and its reverse (186025928161) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 161829520681 - 2¹⁷ = 161829389609 is a prime.

It is a super-2 number, since 2×161829520681² (a number of 23 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (161829520651) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 80914760340 + 80914760341.

It is an arithmetic number, because the mean of its divisors is an integer number (80914760341).

Almost surely, 2^161829520681 is an apocalyptic number.

It is an amenable number.

161829520681 is a deficient number, since it is larger than the sum of its proper divisors (1).

161829520681 is an equidigital number, since it uses as much as digits as its factorization.

161829520681 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 414720, while the sum is 49.

The spelling of 161829520681 in words is "one hundred sixty-one billion, eight hundred twenty-nine million, five hundred twenty thousand, six hundred eighty-one".