191791971 has 24 divisors (see below), whose sum is σ = 319115264. Its totient is φ = 108727920.

The previous prime is 191791967. The next prime is 191791987. The reversal of 191791971 is 179197191.

It is not a de Polignac number, because 191791971 - 2² = 191791967 is a prime.

It is a Smith number, since the sum of its digits (45) coincides with the sum of the digits of its prime factors.

It is a nude number because it is divisible by every one of its digits.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (191791921) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 3985 + ... + 19986.

Almost surely, 2^191791971 is an apocalyptic number.

191791971 is a deficient number, since it is larger than the sum of its proper divisors (127323293).

191791971 is a wasteful number, since it uses less digits than its factorization.

191791971 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 24111 (or 24108 counting only the distinct ones).

The product of its digits is 35721, while the sum is 45.

The square root of 191791971 is about 13848.8978261810. The cubic root of 191791971 is about 576.6913988450.

The spelling of 191791971 in words is "one hundred ninety-one million, seven hundred ninety-one thousand, nine hundred seventy-one".