666020 has 12 divisors (see below), whose sum is σ = 1398684. Its totient is φ = 266400.

The previous prime is 666019. The next prime is 666023. The reversal of 666020 is 20666.

It can be written as a sum of positive squares in 2 ways, for example, as 343396 + 322624 = 586^2 + 568^2 .

It is a Harshad number since it is a multiple of its sum of digits (20), and also a Moran number because the ratio is a prime number: 33301 = 666020 / (6 + 6 + 6 + 0 + 2 + 0).

It is a junction number, because it is equal to n+sod(n) for n = 665983 and 666001.

It is not an unprimeable number, because it can be changed into a prime (666023) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 16631 + ... + 16670.

It is an arithmetic number, because the mean of its divisors is an integer number (116557).

2⁶⁶⁶⁰²⁰ is an apocalyptic number.

It is an amenable number.

666020 is an abundant number, since it is smaller than the sum of its proper divisors (732664).

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

666020 is a wasteful number, since it uses less digits than its factorization.

666020 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 33310 (or 33308 counting only the distinct ones).

The product of its (nonzero) digits is 432, while the sum is 20.

The square root of 666020 is about 816.1004840092. The cubic root of 666020 is about 87.3297915675.

Adding to 666020 its reverse (20666), we get a palindrome (686686).

The spelling of 666020 in words is "six hundred sixty-six thousand, twenty".