16666639 has 4 divisors (see below), whose sum is σ = 18181800. Its totient is φ = 15151480.

The previous prime is 16666631. The next prime is 16666669. The reversal of 16666639 is 93666661.

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

It is a cyclic number.

It is not a de Polignac number, because 16666639 - 2³ = 16666631 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 16666595 and 16666604.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (16666631) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 757564 + ... + 757585.

It is an arithmetic number, because the mean of its divisors is an integer number (4545450).

Almost surely, 2^16666639 is an apocalyptic number.

16666639 is a deficient number, since it is larger than the sum of its proper divisors (1515161).

16666639 is a wasteful number, since it uses less digits than its factorization.

16666639 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1515160.

The product of its digits is 209952, while the sum is 43.

The square root of 16666639 is about 4082.4795161764. The cubic root of 16666639 is about 255.4363361229.

The spelling of 16666639 in words is "sixteen million, six hundred sixty-six thousand, six hundred thirty-nine".