128738191 has 2 divisors, whose sum is σ = 128738192. Its totient is φ = 128738190.

The previous prime is 128738171. The next prime is 128738209. The reversal of 128738191 is 191837821.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-128738191 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (128738111) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 64369095 + 64369096.

It is an arithmetic number, because the mean of its divisors is an integer number (64369096).

Almost surely, 2^128738191 is an apocalyptic number.

128738191 is a deficient number, since it is larger than the sum of its proper divisors (1).

128738191 is an equidigital number, since it uses as much as digits as its factorization.

128738191 is an evil number, because the sum of its binary digits is even.

The product of its digits is 24192, while the sum is 40.

The square root of 128738191 is about 11346.2853392641. The cubic root of 128738191 is about 504.9353784579.

The spelling of 128738191 in words is "one hundred twenty-eight million, seven hundred thirty-eight thousand, one hundred ninety-one".