166591220 has 24 divisors (see below), whose sum is σ = 355773600. Its totient is φ = 65506592.

The previous prime is 166591219. The next prime is 166591223. The reversal of 166591220 is 22195661.

It is a happy number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (166591223) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 69410 + ... + 71769.

It is an arithmetic number, because the mean of its divisors is an integer number (14823900).

Almost surely, 2^166591220 is an apocalyptic number.

166591220 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

166591220 is an abundant number, since it is smaller than the sum of its proper divisors (189182380).

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

166591220 is a wasteful number, since it uses less digits than its factorization.

166591220 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 141247 (or 141245 counting only the distinct ones).

The product of its (nonzero) digits is 6480, while the sum is 32.

The square root of 166591220 is about 12907.0221197610. The cubic root of 166591220 is about 550.2381558143.

The spelling of 166591220 in words is "one hundred sixty-six million, five hundred ninety-one thousand, two hundred twenty".