161131871 has 4 divisors (see below), whose sum is σ = 161480352. Its totient is φ = 160783392.

The previous prime is 161131843. The next prime is 161131889. The reversal of 161131871 is 178131161.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 178131161 = 13 ⋅13702397.

It is a cyclic number.

It is not a de Polignac number, because 161131871 - 2¹⁸ = 160869727 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (161131771) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 173546 + ... + 174471.

It is an arithmetic number, because the mean of its divisors is an integer number (40370088).

Almost surely, 2^161131871 is an apocalyptic number.

161131871 is a deficient number, since it is larger than the sum of its proper divisors (348481).

161131871 is an equidigital number, since it uses as much as digits as its factorization.

161131871 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 348480.

The product of its digits is 1008, while the sum is 29.

The square root of 161131871 is about 12693.7729221851. The cubic root of 161131871 is about 544.1606708495.

The spelling of 161131871 in words is "one hundred sixty-one million, one hundred thirty-one thousand, eight hundred seventy-one".