194128891 has 24 divisors (see below), whose sum is σ = 221205600. Its totient is φ = 170121600.

The previous prime is 194128889. The next prime is 194128897. The reversal of 194128891 is 198821491.

It is a happy number.

It is not a de Polignac number, because 194128891 - 2¹ = 194128889 is a prime.

It is not an unprimeable number, because it can be changed into a prime (194128897) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 540570 + ... + 540928.

It is an arithmetic number, because the mean of its divisors is an integer number (9216900).

Almost surely, 2^194128891 is an apocalyptic number.

194128891 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

194128891 is a deficient number, since it is larger than the sum of its proper divisors (27076709).

194128891 is a wasteful number, since it uses less digits than its factorization.

194128891 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 531 (or 520 counting only the distinct ones).

The product of its digits is 41472, while the sum is 43.

The square root of 194128891 is about 13933.0144261750. The cubic root of 194128891 is about 579.0242124140.

The spelling of 194128891 in words is "one hundred ninety-four million, one hundred twenty-eight thousand, eight hundred ninety-one".