218001191 has 4 divisors (see below), whose sum is σ = 219034584. Its totient is φ = 216967800.

The previous prime is 218001187. The next prime is 218001197. The reversal of 218001191 is 191100812.

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 218001191 - 2² = 218001187 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (218001197) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 516380 + ... + 516801.

It is an arithmetic number, because the mean of its divisors is an integer number (54758646).

Almost surely, 2^218001191 is an apocalyptic number.

218001191 is a deficient number, since it is larger than the sum of its proper divisors (1033393).

218001191 is a wasteful number, since it uses less digits than its factorization.

218001191 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1033392.

The product of its (nonzero) digits is 144, while the sum is 23.

The square root of 218001191 is about 14764.8633925275. The cubic root of 218001191 is about 601.8472615013.

The spelling of 218001191 in words is "two hundred eighteen million, one thousand, one hundred ninety-one".