191640055 has 4 divisors (see below), whose sum is σ = 229968072. Its totient is φ = 153312040.

The previous prime is 191640037. The next prime is 191640107. The reversal of 191640055 is 550046191.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 550046191 = 821 ⋅669971.

It is not a de Polignac number, because 191640055 - 2⁷ = 191639927 is a prime.

It is a Smith number, since the sum of its digits (31) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 191639999 and 191640026.

It is a congruent number.

It is an unprimeable number.

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, 19164001 + ... + 19164010.

It is an arithmetic number, because the mean of its divisors is an integer number (57492018).

Almost surely, 2^191640055 is an apocalyptic number.

191640055 is a deficient number, since it is larger than the sum of its proper divisors (38328017).

191640055 is an equidigital number, since it uses as much as digits as its factorization.

191640055 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 38328016.

The product of its (nonzero) digits is 5400, while the sum is 31.

The square root of 191640055 is about 13843.4119710424. The cubic root of 191640055 is about 576.5390952987.

The spelling of 191640055 in words is "one hundred ninety-one million, six hundred forty thousand, fifty-five".