16666399971 has 32 divisors (see below), whose sum is σ = 27208670720. Its totient is φ = 10017719712.

The previous prime is 16666399957. The next prime is 16666399979. The reversal of 16666399971 is 17999366661.

16666399971 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 16666399971 - 2²⁷ = 16532182243 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 16666399899 and 16666399908.

It is not an unprimeable number, because it can be changed into a prime (16666399979) 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, 537031 + ... + 567216.

It is an arithmetic number, because the mean of its divisors is an integer number (850270960).

Almost surely, 2^16666399971 is an apocalyptic number.

16666399971 is a deficient number, since it is larger than the sum of its proper divisors (10542270749).

16666399971 is a wasteful number, since it uses less digits than its factorization.

16666399971 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1104312 (or 1104306 counting only the distinct ones).

The product of its digits is 19840464, while the sum is 63.

The spelling of 16666399971 in words is "sixteen billion, six hundred sixty-six million, three hundred ninety-nine thousand, nine hundred seventy-one".