1666220 has 12 divisors (see below), whose sum is σ = 3499104. Its totient is φ = 666480.

The previous prime is 1666213. The next prime is 1666237. The reversal of 1666220 is 226661.

It is a hoax number, since the sum of its digits (23) coincides with the sum of the digits of its distinct prime factors.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 41636 + ... + 41675.

It is an arithmetic number, because the mean of its divisors is an integer number (291592).

2^1666220 is an apocalyptic number.

1666220 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1666220 is an abundant number, since it is smaller than the sum of its proper divisors (1832884).

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

1666220 is a wasteful number, since it uses less digits than its factorization.

1666220 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 83320 (or 83318 counting only the distinct ones).

The product of its (nonzero) digits is 864, while the sum is 23.

The square root of 1666220 is about 1290.8214438876. The cubic root of 1666220 is about 118.5525175655.

The spelling of 1666220 in words is "one million, six hundred sixty-six thousand, two hundred twenty".