166665647 has 8 divisors (see below), whose sum is σ = 168042240. Its totient is φ = 165294360.

The previous prime is 166665601. The next prime is 166665683. The reversal of 166665647 is 746566661.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 166665647 - 2²² = 162471343 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (166665347) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 81872 + ... + 83882.

It is an arithmetic number, because the mean of its divisors is an integer number (21005280).

Almost surely, 2^166665647 is an apocalyptic number.

166665647 is a deficient number, since it is larger than the sum of its proper divisors (1376593).

166665647 is a wasteful number, since it uses less digits than its factorization.

166665647 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2653.

The product of its digits is 1088640, while the sum is 47.

The square root of 166665647 is about 12909.9049957775. The cubic root of 166665647 is about 550.3200858584.

The spelling of 166665647 in words is "one hundred sixty-six million, six hundred sixty-five thousand, six hundred forty-seven".