991671980719841 has 16 divisors (see below), whose sum is σ = 1014872277382656. Its totient is φ = 968559304882176.

The previous prime is 991671980719697. The next prime is 991671980719879. The reversal of 991671980719841 is 148917089176199.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-991671980719841 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (991671980749841) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1155396845 + ... + 1156254821.

It is an arithmetic number, because the mean of its divisors is an integer number (63429517336416).

Almost surely, 2^{991671980719841} is an apocalyptic number.

It is an amenable number.

991671980719841 is a deficient number, since it is larger than the sum of its proper divisors (23200296662815).

991671980719841 is a wasteful number, since it uses less digits than its factorization.

991671980719841 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 909008.

The product of its (nonzero) digits is 493807104, while the sum is 80.

The spelling of 991671980719841 in words is "nine hundred ninety-one trillion, six hundred seventy-one billion, nine hundred eighty million, seven hundred nineteen thousand, eight hundred forty-one".