166565205840 has 320 divisors, whose sum is σ = 580483418112. Its totient is φ = 39154636800.

The previous prime is 166565205817. The next prime is 166565205841. The reversal of 166565205840 is 48502565661.

It is a Harshad number since it is a multiple of its sum of digits (48).

It is a self number, because there is not a number n which added to its sum of digits gives 166565205840.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (166565205841) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 30375739 + ... + 30381221.

Almost surely, 2^166565205840 is an apocalyptic number.

166565205840 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 166565205840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (290241709056).

166565205840 is an abundant number, since it is smaller than the sum of its proper divisors (413918212272).

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

166565205840 is a wasteful number, since it uses less digits than its factorization.

166565205840 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5858 (or 5852 counting only the distinct ones).

The product of its (nonzero) digits is 1728000, while the sum is 48.

The spelling of 166565205840 in words is "one hundred sixty-six billion, five hundred sixty-five million, two hundred five thousand, eight hundred forty".