191927891 has 4 divisors (see below), whose sum is σ = 192636384. Its totient is φ = 191219400.

The previous prime is 191927881. The next prime is 191927927. The reversal of 191927891 is 198729191.

191927891 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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 191927891 - 2¹⁴ = 191911507 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (191927881) 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, 353840 + ... + 354381.

It is an arithmetic number, because the mean of its divisors is an integer number (48159096).

Almost surely, 2^191927891 is an apocalyptic number.

191927891 is a deficient number, since it is larger than the sum of its proper divisors (708493).

191927891 is an equidigital number, since it uses as much as digits as its factorization.

191927891 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 708492.

The product of its digits is 81648, while the sum is 47.

The square root of 191927891 is about 13853.8042067874. The cubic root of 191927891 is about 576.8275974309.

The spelling of 191927891 in words is "one hundred ninety-one million, nine hundred twenty-seven thousand, eight hundred ninety-one".