1666666647 has 6 divisors (see below), whose sum is σ = 2407407392. Its totient is φ = 1111111092.

The previous prime is 1666666637. The next prime is 1666666649. The reversal of 1666666647 is 7466666661.

It is not a de Polignac number, because 1666666647 - 2¹² = 1666662551 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 1666666593 and 1666666602.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1666666649) 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, 92592583 + ... + 92592600.

Almost surely, 2^1666666647 is an apocalyptic number.

1666666647 is a deficient number, since it is larger than the sum of its proper divisors (740740745).

1666666647 is a wasteful number, since it uses less digits than its factorization.

1666666647 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 185185189 (or 185185186 counting only the distinct ones).

The product of its digits is 7838208, while the sum is 54.

The square root of 1666666647 is about 40824.8288055198. The cubic root of 1666666647 is about 1185.6310968332.

The spelling of 1666666647 in words is "one billion, six hundred sixty-six million, six hundred sixty-six thousand, six hundred forty-seven".