166564820 has 24 divisors (see below), whose sum is σ = 350111328. Its totient is φ = 66564000.

The previous prime is 166564819. The next prime is 166564883. The reversal of 166564820 is 28465661.

It is a Smith number, since the sum of its digits (38) coincides with the sum of the digits of its prime factors.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 22595 + ... + 29045.

It is an arithmetic number, because the mean of its divisors is an integer number (14587972).

Almost surely, 2^166564820 is an apocalyptic number.

166564820 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

166564820 is an abundant number, since it is smaller than the sum of its proper divisors (183546508).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

166564820 is a wasteful number, since it uses less digits than its factorization.

166564820 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7751 (or 7749 counting only the distinct ones).

The product of its (nonzero) digits is 69120, while the sum is 38.

The square root of 166564820 is about 12905.9993801333. Note that the first 3 decimals coincide. The cubic root of 166564820 is about 550.2090885467.

The spelling of 166564820 in words is "one hundred sixty-six million, five hundred sixty-four thousand, eight hundred twenty".