191028939 has 4 divisors (see below), whose sum is σ = 254705256. Its totient is φ = 127352624.

The previous prime is 191028923. The next prime is 191028941. The reversal of 191028939 is 939820191.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 939820191 = 3 ⋅313273397.

It is a cyclic number.

It is not a de Polignac number, because 191028939 - 2⁴ = 191028923 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 191028939.

It is not an unprimeable number, because it can be changed into a prime (191028139) 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 3 ways as a sum of consecutive naturals, for example, 31838154 + ... + 31838159.

It is an arithmetic number, because the mean of its divisors is an integer number (63676314).

Almost surely, 2^191028939 is an apocalyptic number.

191028939 is a deficient number, since it is larger than the sum of its proper divisors (63676317).

191028939 is an equidigital number, since it uses as much as digits as its factorization.

191028939 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 63676316.

The product of its (nonzero) digits is 34992, while the sum is 42.

The square root of 191028939 is about 13821.3218977057. The cubic root of 191028939 is about 575.9256058674.

The spelling of 191028939 in words is "one hundred ninety-one million, twenty-eight thousand, nine hundred thirty-nine".