191271697 has 4 divisors (see below), whose sum is σ = 195719920. Its totient is φ = 186823476.

The previous prime is 191271677. The next prime is 191271701. The reversal of 191271697 is 796172191.

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: 796172191 = 79 ⋅10078129.

It is not a de Polignac number, because 191271697 - 2¹⁹ = 190747409 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (43), and also a Moran number because the ratio is a prime number: 4448179 = 191271697 / (1 + 9 + 1 + 2 + 7 + 1 + 6 + 9 + 7).

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (191271677) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2224047 + ... + 2224132.

It is an arithmetic number, because the mean of its divisors is an integer number (48929980).

Almost surely, 2^191271697 is an apocalyptic number.

191271697 is the 7393-rd centered heptagonal number.

It is an amenable number.

191271697 is a deficient number, since it is larger than the sum of its proper divisors (4448223).

191271697 is an equidigital number, since it uses as much as digits as its factorization.

191271697 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4448222.

The product of its digits is 47628, while the sum is 43.

The square root of 191271697 is about 13830.1011203823. The cubic root of 191271697 is about 576.1694631025.

The spelling of 191271697 in words is "one hundred ninety-one million, two hundred seventy-one thousand, six hundred ninety-seven".