128211191 has 4 divisors (see below), whose sum is σ = 128245800. Its totient is φ = 128176584.

The previous prime is 128211163. The next prime is 128211197. The reversal of 128211191 is 191112821.

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 128211191 - 2¹⁸ = 127949047 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 128211191.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (128211197) 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, 10976 + ... + 19413.

It is an arithmetic number, because the mean of its divisors is an integer number (32061450).

Almost surely, 2^128211191 is an apocalyptic number.

128211191 is a deficient number, since it is larger than the sum of its proper divisors (34609).

128211191 is an equidigital number, since it uses as much as digits as its factorization.

128211191 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 34608.

The product of its digits is 288, while the sum is 26.

The square root of 128211191 is about 11323.0380640533. The cubic root of 128211191 is about 504.2454384793.

The spelling of 128211191 in words is "one hundred twenty-eight million, two hundred eleven thousand, one hundred ninety-one".