161780977 has 2 divisors, whose sum is σ = 161780978. Its totient is φ = 161780976.

The previous prime is 161780933. The next prime is 161780999. The reversal of 161780977 is 779087161.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 127780416 + 34000561 = 11304^2 + 5831^2 .

It is an emirp because it is prime and its reverse (779087161) is a distict prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-161780977 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (161780477) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 80890488 + 80890489.

It is an arithmetic number, because the mean of its divisors is an integer number (80890489).

Almost surely, 2^161780977 is an apocalyptic number.

161780977 is the 7344-th hex number.

It is an amenable number.

161780977 is a deficient number, since it is larger than the sum of its proper divisors (1).

161780977 is an equidigital number, since it uses as much as digits as its factorization.

161780977 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 148176, while the sum is 46.

The square root of 161780977 is about 12719.3151152096. The cubic root of 161780977 is about 544.8903934675.

The spelling of 161780977 in words is "one hundred sixty-one million, seven hundred eighty thousand, nine hundred seventy-seven".