161871231 has 4 divisors (see below), whose sum is σ = 215828312. Its totient is φ = 107914152.

The previous prime is 161871209. The next prime is 161871233. The reversal of 161871231 is 132178161.

It is a semiprime because it is the product of two primes.

It is not a de Polignac number, because 161871231 - 2⁶ = 161871167 is a prime.

It is a super-2 number, since 2×161871231² = 52404590850910722, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (161871233) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 26978536 + ... + 26978541.

It is an arithmetic number, because the mean of its divisors is an integer number (53957078).

Almost surely, 2^161871231 is an apocalyptic number.

161871231 is a deficient number, since it is larger than the sum of its proper divisors (53957081).

161871231 is an equidigital number, since it uses as much as digits as its factorization.

161871231 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 53957080.

The product of its digits is 2016, while the sum is 30.

The square root of 161871231 is about 12722.8625316789. The cubic root of 161871231 is about 544.9917020312.

The spelling of 161871231 in words is "one hundred sixty-one million, eight hundred seventy-one thousand, two hundred thirty-one".