191671994991 has 32 divisors (see below), whose sum is σ = 264887700480. Its totient is φ = 123203856384.

The previous prime is 191671994981. The next prime is 191671995001. The reversal of 191671994991 is 199499176191.

It is an interprime number because it is at equal distance from previous prime (191671994981) and next prime (191671995001).

It is not a de Polignac number, because 191671994991 - 2⁷ = 191671994863 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (191671994981) 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 31 ways as a sum of consecutive naturals, for example, 9078175 + ... + 9099263.

It is an arithmetic number, because the mean of its divisors is an integer number (8277740640).

Almost surely, 2^191671994991 is an apocalyptic number.

191671994991 is a deficient number, since it is larger than the sum of its proper divisors (73215705489).

191671994991 is a wasteful number, since it uses less digits than its factorization.

191671994991 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 22095.

The product of its digits is 9920232, while the sum is 66.

The spelling of 191671994991 in words is "one hundred ninety-one billion, six hundred seventy-one million, nine hundred ninety-four thousand, nine hundred ninety-one".