1191201191 has 4 divisors (see below), whose sum is σ = 1191271872. Its totient is φ = 1191130512.

The previous prime is 1191201173. The next prime is 1191201223. The reversal of 1191201191 is 1911021911.

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.

It is a cyclic number.

It is not a de Polignac number, because 1191201191 - 2⁶ = 1191201127 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 1191201191.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1191200191) 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, 6275 + ... + 49211.

It is an arithmetic number, because the mean of its divisors is an integer number (297817968).

Almost surely, 2^1191201191 is an apocalyptic number.

1191201191 is a deficient number, since it is larger than the sum of its proper divisors (70681).

1191201191 is an equidigital number, since it uses as much as digits as its factorization.

1191201191 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 70680.

The product of its (nonzero) digits is 162, while the sum is 26.

The square root of 1191201191 is about 34513.7826237577. The cubic root of 1191201191 is about 1060.0549369296.

The spelling of 1191201191 in words is "one billion, one hundred ninety-one million, two hundred one thousand, one hundred ninety-one".