128478191 has 4 divisors (see below), whose sum is σ = 129657000. Its totient is φ = 127299384.

The previous prime is 128478157. The next prime is 128478193. The reversal of 128478191 is 191874821.

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 128478191 - 2⁶ = 128478127 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 (128478193) 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, 589241 + ... + 589458.

It is an arithmetic number, because the mean of its divisors is an integer number (32414250).

Almost surely, 2^128478191 is an apocalyptic number.

128478191 is a deficient number, since it is larger than the sum of its proper divisors (1178809).

128478191 is a wasteful number, since it uses less digits than its factorization.

128478191 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1178808.

The product of its digits is 32256, while the sum is 41.

The square root of 128478191 is about 11334.8220541833. The cubic root of 128478191 is about 504.5952264108.

The spelling of 128478191 in words is "one hundred twenty-eight million, four hundred seventy-eight thousand, one hundred ninety-one".