166564566 has 64 divisors (see below), whose sum is σ = 428198400. Its totient is φ = 47007648.

The previous prime is 166564561. The next prime is 166564571. The reversal of 166564566 is 665465661.

It is an interprime number because it is at equal distance from previous prime (166564561) and next prime (166564571).

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (166564561) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 28720 + ... + 34028.

It is an arithmetic number, because the mean of its divisors is an integer number (6690600).

Almost surely, 2^166564566 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 166564566, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (214099200).

166564566 is an abundant number, since it is smaller than the sum of its proper divisors (261633834).

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

166564566 is a wasteful number, since it uses less digits than its factorization.

166564566 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5410 (or 5404 counting only the distinct ones).

The product of its digits is 777600, while the sum is 45.

The square root of 166564566 is about 12905.9895397447. The cubic root of 166564566 is about 550.2088088694.

The spelling of 166564566 in words is "one hundred sixty-six million, five hundred sixty-four thousand, five hundred sixty-six".