191231994766 has 4 divisors (see below), whose sum is σ = 286847992152. Its totient is φ = 95615997382.

The previous prime is 191231994761. The next prime is 191231994781. The reversal of 191231994766 is 667499132191.

It is a semiprime because it is the product of two primes.

It is a self number, because there is not a number n which added to its sum of digits gives 191231994766.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (191231994761) 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 as a sum of consecutive naturals, namely, 47807998690 + ... + 47807998693.

It is an arithmetic number, because the mean of its divisors is an integer number (71711998038).

Almost surely, 2^191231994766 is an apocalyptic number.

191231994766 is a deficient number, since it is larger than the sum of its proper divisors (95615997386).

191231994766 is an equidigital number, since it uses as much as digits as its factorization.

191231994766 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 95615997385.

The product of its digits is 4408992, while the sum is 58.

The spelling of 191231994766 in words is "one hundred ninety-one billion, two hundred thirty-one million, nine hundred ninety-four thousand, seven hundred sixty-six".