166445815 has 4 divisors (see below), whose sum is σ = 199734984. Its totient is φ = 133156648.

The previous prime is 166445813. The next prime is 166445843. The reversal of 166445815 is 518544661.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 518544661 = 293 ⋅1769777.

It is a cyclic number.

It is not a de Polignac number, because 166445815 - 2¹ = 166445813 is a prime.

It is a Smith number, since the sum of its digits (40) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (166445813) 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, 16644577 + ... + 16644586.

It is an arithmetic number, because the mean of its divisors is an integer number (49933746).

Almost surely, 2^166445815 is an apocalyptic number.

166445815 is a deficient number, since it is larger than the sum of its proper divisors (33289169).

166445815 is an equidigital number, since it uses as much as digits as its factorization.

166445815 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 33289168.

The product of its digits is 115200, while the sum is 40.

The square root of 166445815 is about 12901.3881036112. The cubic root of 166445815 is about 550.0780219893.

The spelling of 166445815 in words is "one hundred sixty-six million, four hundred forty-five thousand, eight hundred fifteen".