166785220 has 36 divisors (see below), whose sum is σ = 407434860. Its totient is φ = 57183168.

The previous prime is 166785209. The next prime is 166785221. The reversal of 166785220 is 22587661.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 51179716 + 115605504 = 7154^2 + 10752^2 .

It is a super-2 number, since 2×166785220² = 55634619220896800, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 166785220.

It is not an unprimeable number, because it can be changed into a prime (166785221) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 84115 + ... + 86074.

It is an arithmetic number, because the mean of its divisors is an integer number (11317635).

Almost surely, 2^166785220 is an apocalyptic number.

166785220 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

166785220 is an abundant number, since it is smaller than the sum of its proper divisors (240649640).

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

166785220 is a wasteful number, since it uses less digits than its factorization.

166785220 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 170212 (or 170203 counting only the distinct ones).

The product of its (nonzero) digits is 40320, while the sum is 37.

The square root of 166785220 is about 12914.5352219892. The cubic root of 166785220 is about 550.4516620498.

The spelling of 166785220 in words is "one hundred sixty-six million, seven hundred eighty-five thousand, two hundred twenty".