161871859 has 4 divisors (see below), whose sum is σ = 161897904. Its totient is φ = 161845816.

The previous prime is 161871839. The next prime is 161871883. The reversal of 161871859 is 958178161.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is not a de Polignac number, because 161871859 - 2¹¹ = 161869811 is a prime.

It is a super-2 number, since 2×161871859² = 52404997472231762, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (161871839) 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, 2349 + ... + 18145.

It is an arithmetic number, because the mean of its divisors is an integer number (40474476).

Almost surely, 2^161871859 is an apocalyptic number.

161871859 is a deficient number, since it is larger than the sum of its proper divisors (26045).

161871859 is a wasteful number, since it uses less digits than its factorization.

161871859 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 26044.

The product of its digits is 120960, while the sum is 46.

The square root of 161871859 is about 12722.8872116356. The cubic root of 161871859 is about 544.9924068184.

The spelling of 161871859 in words is "one hundred sixty-one million, eight hundred seventy-one thousand, eight hundred fifty-nine".