161080781 has 2 divisors, whose sum is σ = 161080782. Its totient is φ = 161080780.

The previous prime is 161080757. The next prime is 161080811. The reversal of 161080781 is 187080161.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 102313225 + 58767556 = 10115^2 + 7666^2 .

It is an emirp because it is prime and its reverse (187080161) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 161080781 - 2¹⁰ = 161079757 is a prime.

It is a super-2 number, since 2×161080781² = 51894036015139922, which contains 22 as substring.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (161080481) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 80540390 + 80540391.

It is an arithmetic number, because the mean of its divisors is an integer number (80540391).

Almost surely, 2^161080781 is an apocalyptic number.

It is an amenable number.

161080781 is a deficient number, since it is larger than the sum of its proper divisors (1).

161080781 is an equidigital number, since it uses as much as digits as its factorization.

161080781 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 2688, while the sum is 32.

The square root of 161080781 is about 12691.7603585949. The cubic root of 161080781 is about 544.1031525214.

The spelling of 161080781 in words is "one hundred sixty-one million, eighty thousand, seven hundred eighty-one".