191881 has 4 divisors (see below), whose sum is σ = 202000. Its totient is φ = 181764.

The previous prime is 191861. The next prime is 191899. The reversal of 191881 is 188191.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 188191 = 307 ⋅613.

It is a cyclic number.

It is not a de Polignac number, because 191881 - 2¹⁵ = 159113 is a prime.

It is a super-2 number, since 2×191881² = 73636636322, which contains 22 as substring.

It is a Duffinian number.

191881 is a modest number, since divided by 1881 gives 19 as remainder.

It is not an unprimeable number, because it can be changed into a prime (191801) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 5031 + ... + 5068.

It is an arithmetic number, because the mean of its divisors is an integer number (50500).

2¹⁹¹⁸⁸¹ is an apocalyptic number.

It is an amenable number.

191881 is a deficient number, since it is larger than the sum of its proper divisors (10119).

191881 is a wasteful number, since it uses less digits than its factorization.

191881 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10118.

The product of its digits is 576, while the sum is 28.

The square root of 191881 is about 438.0422354066. The cubic root of 191881 is about 57.6780617589.

The spelling of 191881 in words is "one hundred ninety-one thousand, eight hundred eighty-one".