161780657 has 2 divisors, whose sum is σ = 161780658. Its totient is φ = 161780656.

The previous prime is 161780609. The next prime is 161780681. The reversal of 161780657 is 756087161.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 88661056 + 73119601 = 9416^2 + 8551^2 .

It is a cyclic number.

It is not a de Polignac number, because 161780657 - 2⁸ = 161780401 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (161780057) 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, 80890328 + 80890329.

It is an arithmetic number, because the mean of its divisors is an integer number (80890329).

Almost surely, 2^161780657 is an apocalyptic number.

It is an amenable number.

161780657 is a deficient number, since it is larger than the sum of its proper divisors (1).

161780657 is an equidigital number, since it uses as much as digits as its factorization.

161780657 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 70560, while the sum is 41.

The square root of 161780657 is about 12719.3025359097. The cubic root of 161780657 is about 544.8900342060.

The spelling of 161780657 in words is "one hundred sixty-one million, seven hundred eighty thousand, six hundred fifty-seven".