1991066686684 has 24 divisors (see below), whose sum is σ = 3486510059648. Its totient is φ = 994921092720.

The previous prime is 1991066686669. The next prime is 1991066686691. The reversal of 1991066686684 is 4866866601991.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 96032599 + ... + 96053329.

Almost surely, 2^{1991066686684} is an apocalyptic number.

It is an amenable number.

1991066686684 is a deficient number, since it is larger than the sum of its proper divisors (1495443372964).

1991066686684 is a wasteful number, since it uses less digits than its factorization.

1991066686684 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 34345 (or 34343 counting only the distinct ones).

The product of its (nonzero) digits is 161243136, while the sum is 70.

The spelling of 1991066686684 in words is "one trillion, nine hundred ninety-one billion, sixty-six million, six hundred eighty-six thousand, six hundred eighty-four".