161761811 has 2 divisors, whose sum is σ = 161761812. Its totient is φ = 161761810.

The previous prime is 161761807. The next prime is 161761819. The reversal of 161761811 is 118167161.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 161761811 - 2² = 161761807 is a prime.

It is not a weakly prime, because it can be changed into another prime (161761819) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 80880905 + 80880906.

It is an arithmetic number, because the mean of its divisors is an integer number (80880906).

Almost surely, 2^161761811 is an apocalyptic number.

161761811 is a deficient number, since it is larger than the sum of its proper divisors (1).

161761811 is an equidigital number, since it uses as much as digits as its factorization.

161761811 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 2016, while the sum is 32.

The square root of 161761811 is about 12718.5616718244. The cubic root of 161761811 is about 544.8688751121.

The spelling of 161761811 in words is "one hundred sixty-one million, seven hundred sixty-one thousand, eight hundred eleven".