166666645 has 4 divisors (see below), whose sum is σ = 199999980. Its totient is φ = 133333312.

The previous prime is 166666639. The next prime is 166666649. The reversal of 166666645 is 546666661.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 546666661 = 5749 ⋅95089.

It can be written as a sum of positive squares in 2 ways, for example, as 47900241 + 118766404 = 6921^2 + 10898^2 .

It is a cyclic number.

It is not a de Polignac number, because 166666645 - 2³ = 166666637 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 166666595 and 166666604.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (166666649) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 16666660 + ... + 16666669.

It is an arithmetic number, because the mean of its divisors is an integer number (49999995).

Almost surely, 2^166666645 is an apocalyptic number.

It is an amenable number.

166666645 is a deficient number, since it is larger than the sum of its proper divisors (33333335).

166666645 is an equidigital number, since it uses as much as digits as its factorization.

166666645 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 33333334.

The product of its digits is 933120, while the sum is 46.

The square root of 166666645 is about 12909.9436482116. The cubic root of 166666645 is about 550.3211843019.

The spelling of 166666645 in words is "one hundred sixty-six million, six hundred sixty-six thousand, six hundred forty-five".