166581640 has 64 divisors (see below), whose sum is σ = 414149760. Its totient is φ = 59980800.

The previous prime is 166581629. The next prime is 166581641. The reversal of 166581640 is 46185661.

It is a Smith number, since the sum of its digits (37) coincides with the sum of the digits of its prime factors.

It is a self number, because there is not a number n which added to its sum of digits gives 166581640.

It is not an unprimeable number, because it can be changed into a prime (166581641) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 10315 + ... + 20965.

It is an arithmetic number, because the mean of its divisors is an integer number (6471090).

Almost surely, 2^166581640 is an apocalyptic number.

166581640 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 166581640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (207074880).

166581640 is an abundant number, since it is smaller than the sum of its proper divisors (247568120).

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

166581640 is a wasteful number, since it uses less digits than its factorization.

166581640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10702 (or 10698 counting only the distinct ones).

The product of its (nonzero) digits is 34560, while the sum is 37.

The square root of 166581640 is about 12906.6509986131. The cubic root of 166581640 is about 550.2276082745.

The spelling of 166581640 in words is "one hundred sixty-six million, five hundred eighty-one thousand, six hundred forty".