161995771 has 12 divisors (see below), whose sum is σ = 196671568. Its totient is φ = 130684032.

The previous prime is 161995763. The next prime is 161995781. The reversal of 161995771 is 177599161.

It is not a de Polignac number, because 161995771 - 2³ = 161995763 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (161995721) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 38016 + ... + 42061.

Almost surely, 2^161995771 is an apocalyptic number.

161995771 is a deficient number, since it is larger than the sum of its proper divisors (34675797).

161995771 is an equidigital number, since it uses as much as digits as its factorization.

161995771 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 80118 (or 80101 counting only the distinct ones).

The product of its digits is 119070, while the sum is 46.

The square root of 161995771 is about 12727.7559294638. The cubic root of 161995771 is about 545.1314342263.

The spelling of 161995771 in words is "one hundred sixty-one million, nine hundred ninety-five thousand, seven hundred seventy-one".