666601020 has 72 divisors (see below), whose sum is σ = 2025572640. Its totient is φ = 177448320.

The previous prime is 666600947. The next prime is 666601021. The reversal of 666601020 is 20106666.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (666601021) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 110646 + ... + 116514.

Almost surely, 2^666601020 is an apocalyptic number.

666601020 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

666601020 is an abundant number, since it is smaller than the sum of its proper divisors (1358971620).

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

666601020 is a wasteful number, since it uses less digits than its factorization.

666601020 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6515 (or 6510 counting only the distinct ones).

The product of its (nonzero) digits is 2592, while the sum is 27.

The square root of 666601020 is about 25818.6177011861. The cubic root of 666601020 is about 873.5517899723.

Adding to 666601020 its reverse (20106666), we get a palindrome (686707686).

The spelling of 666601020 in words is "six hundred sixty-six million, six hundred one thousand, twenty".