166918628785 has 4 divisors (see below), whose sum is σ = 200302354548. Its totient is φ = 133534903024.

The previous prime is 166918628783. The next prime is 166918628797. The reversal of 166918628785 is 587826819661.

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

It can be written as a sum of positive squares in 2 ways, for example, as 107093871504 + 59824757281 = 327252^2 + 244591^2 .

It is a cyclic number.

It is not a de Polignac number, because 166918628785 - 2¹ = 166918628783 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 166918628785.

It is not an unprimeable number, because it can be changed into a prime (166918628783) 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, 16691862874 + ... + 16691862883.

It is an arithmetic number, because the mean of its divisors is an integer number (50075588637).

Almost surely, 2^166918628785 is an apocalyptic number.

It is an amenable number.

166918628785 is a deficient number, since it is larger than the sum of its proper divisors (33383725763).

166918628785 is an equidigital number, since it uses as much as digits as its factorization.

166918628785 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 33383725762.

The product of its digits is 69672960, while the sum is 67.

The spelling of 166918628785 in words is "one hundred sixty-six billion, nine hundred eighteen million, six hundred twenty-eight thousand, seven hundred eighty-five".