6661620 has 144 divisors (see below), whose sum is σ = 24530688. Its totient is φ = 1428480.

The previous prime is 6661601. The next prime is 6661643. The reversal of 6661620 is 261666.

6661620 is digitally balanced in base 5, because in such base it contains all the possibile digits an equal number of times.

It is a congruent number.

It is an unprimeable number.

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 47 ways as a sum of consecutive naturals, for example, 21265 + ... + 21575.

It is an arithmetic number, because the mean of its divisors is an integer number (170352).

Almost surely, 2^6661620 is an apocalyptic number.

6661620 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 6661620, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (12265344).

6661620 is an abundant number, since it is smaller than the sum of its proper divisors (17869068).

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

6661620 is a wasteful number, since it uses less digits than its factorization.

6661620 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 350 (or 345 counting only the distinct ones).

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

The square root of 6661620 is about 2581.0114296531. The cubic root of 6661620 is about 188.1597028360.

The spelling of 6661620 in words is "six million, six hundred sixty-one thousand, six hundred twenty".