166664987 has 4 divisors (see below), whose sum is σ = 166803600. Its totient is φ = 166526376.

The previous prime is 166664963. The next prime is 166665011. The reversal of 166664987 is 789466661.

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

It is an interprime number because it is at equal distance from previous prime (166664963) and next prime (166665011).

It is a cyclic number.

It is not a de Polignac number, because 166664987 - 2²⁶ = 99556123 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (166664387) 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 3 ways as a sum of consecutive naturals, for example, 67487 + ... + 69912.

It is an arithmetic number, because the mean of its divisors is an integer number (41700900).

Almost surely, 2^166664987 is an apocalyptic number.

166664987 is a deficient number, since it is larger than the sum of its proper divisors (138613).

166664987 is a wasteful number, since it uses less digits than its factorization.

166664987 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 138612.

The product of its digits is 2612736, while the sum is 53.

The square root of 166664987 is about 12909.8794339839. The cubic root of 166664987 is about 550.3193594305.

The spelling of 166664987 in words is "one hundred sixty-six million, six hundred sixty-four thousand, nine hundred eighty-seven".