19666549611 has 6 divisors (see below), whose sum is σ = 28407238340. Its totient is φ = 13111033068.

The previous prime is 19666549589. The next prime is 19666549631. The reversal of 19666549611 is 11694566691.

It is a de Polignac number, because none of the positive numbers 2^k-19666549611 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (19666549631) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 1092586081 + ... + 1092586098.

Almost surely, 2^19666549611 is an apocalyptic number.

19666549611 is a deficient number, since it is larger than the sum of its proper divisors (8740688729).

19666549611 is a wasteful number, since it uses less digits than its factorization.

19666549611 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2185172185 (or 2185172182 counting only the distinct ones).

The product of its digits is 2099520, while the sum is 54.

The spelling of 19666549611 in words is "nineteen billion, six hundred sixty-six million, five hundred forty-nine thousand, six hundred eleven".