191887 has 4 divisors (see below), whose sum is σ = 192816. Its totient is φ = 190960.

The previous prime is 191861. The next prime is 191899. The reversal of 191887 is 788191.

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, and also an emirpimes, since its reverse is a distinct semiprime: 788191 = 29 ⋅27179.

It is a cyclic number.

It is not a de Polignac number, because 191887 - 2¹⁵ = 159119 is a prime.

It is an Ulam number.

It is a Duffinian number.

191887 is a lucky number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (191827) 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, 3 + ... + 619.

It is an arithmetic number, because the mean of its divisors is an integer number (48204).

2¹⁹¹⁸⁸⁷ is an apocalyptic number.

191887 is a deficient number, since it is larger than the sum of its proper divisors (929).

191887 is an equidigital number, since it uses as much as digits as its factorization.

191887 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 928.

The product of its digits is 4032, while the sum is 34.

The square root of 191887 is about 438.0490840077. The cubic root of 191887 is about 57.6786629384.

It can be divided in two parts, 19 and 1887, that multiplied together give a palindrome (35853).

The spelling of 191887 in words is "one hundred ninety-one thousand, eight hundred eighty-seven".