166851868653 has 10 divisors (see below), whose sum is σ = 249247853294. Its totient is φ = 111234579048.

The previous prime is 166851868639. The next prime is 166851868657. The reversal of 166851868653 is 356868158661.

It is a happy number.

166851868653 is a `hidden beast` number, since 1 + 6 + 6 + 8 + 518 + 68 + 6 + 53 = 666.

It can be written as a sum of positive squares in only one way, i.e., 149365244484 + 17486624169 = 386478^2 + 132237^2 .

It is not a de Polignac number, because 166851868653 - 2²⁸ = 166583433197 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (166851868657) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 9 ways as a sum of consecutive naturals, for example, 1029949726 + ... + 1029949887.

Almost surely, 2^166851868653 is an apocalyptic number.

It is an amenable number.

166851868653 is a deficient number, since it is larger than the sum of its proper divisors (82395984641).

166851868653 is an equidigital number, since it uses as much as digits as its factorization.

166851868653 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2059899625 (or 2059899616 counting only the distinct ones).

The product of its digits is 49766400, while the sum is 63.

The spelling of 166851868653 in words is "one hundred sixty-six billion, eight hundred fifty-one million, eight hundred sixty-eight thousand, six hundred fifty-three".