128321191 has 2 divisors, whose sum is σ = 128321192. Its totient is φ = 128321190.

The previous prime is 128321177. The next prime is 128321197. The reversal of 128321191 is 191123821.

128321191 is nontrivially palindromic in base 16.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 128321191 - 2¹⁵ = 128288423 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (128321197) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 64160595 + 64160596.

It is an arithmetic number, because the mean of its divisors is an integer number (64160596).

Almost surely, 2^128321191 is an apocalyptic number.

128321191 is a deficient number, since it is larger than the sum of its proper divisors (1).

128321191 is an equidigital number, since it uses as much as digits as its factorization.

128321191 is an evil number, because the sum of its binary digits is even.

The product of its digits is 864, while the sum is 28.

The square root of 128321191 is about 11327.8943762731. The cubic root of 128321191 is about 504.3896046334.

The spelling of 128321191 in words is "one hundred twenty-eight million, three hundred twenty-one thousand, one hundred ninety-one".