6661665220 has 96 divisors (see below), whose sum is σ = 17215752960. Its totient is φ = 2113167360.

The previous prime is 6661665193. The next prime is 6661665233. The reversal of 6661665220 is 225661666.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 116700 + ... + 164140.

It is an arithmetic number, because the mean of its divisors is an integer number (179330760).

Almost surely, 2^6661665220 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 6661665220, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (8607876480).

6661665220 is an abundant number, since it is smaller than the sum of its proper divisors (10554087740).

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

6661665220 is a wasteful number, since it uses less digits than its factorization.

6661665220 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 47533 (or 47531 counting only the distinct ones).

The product of its (nonzero) digits is 155520, while the sum is 40.

The square root of 6661665220 is about 81619.0248655300. The cubic root of 6661665220 is about 1881.6012858644.

The spelling of 6661665220 in words is "six billion, six hundred sixty-one million, six hundred sixty-five thousand, two hundred twenty".