191971 has 4 divisors (see below), whose sum is σ = 206752. Its totient is φ = 177192.

The previous prime is 191969. The next prime is 191977. The reversal of 191971 is 179191.

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

It is a cyclic number.

It is not a de Polignac number, because 191971 - 2¹ = 191969 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (191977) 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, 7371 + ... + 7396.

It is an arithmetic number, because the mean of its divisors is an integer number (51688).

2¹⁹¹⁹⁷¹ is an apocalyptic number.

191971 is a deficient number, since it is larger than the sum of its proper divisors (14781).

191971 is a wasteful number, since it uses less digits than its factorization.

191971 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 14780.

The product of its digits is 567, while the sum is 28.

The square root of 191971 is about 438.1449531833. The cubic root of 191971 is about 57.6870781357.

The spelling of 191971 in words is "one hundred ninety-one thousand, nine hundred seventy-one".