2021666381280 has 768 divisors, whose sum is σ = 9221024655360. Its totient is φ = 401456922624.

The previous prime is 2021666381197. The next prime is 2021666381281. The reversal of 2021666381280 is 821836661202.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2021666381281) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 127 ways as a sum of consecutive naturals, for example, 6531787 + ... + 6834293.

It is an arithmetic number, because the mean of its divisors is an integer number (12006542520).

Almost surely, 2^{2021666381280} is an apocalyptic number.

2021666381280 is a gapful number since it is divisible by the number (20) 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 2021666381280, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (4610512327680).

2021666381280 is an abundant number, since it is smaller than the sum of its proper divisors (7199358274080).

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

2021666381280 is a wasteful number, since it uses less digits than its factorization.

2021666381280 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 302568 (or 302554 counting only the distinct ones).

The product of its (nonzero) digits is 331776, while the sum is 45.

The spelling of 2021666381280 in words is "two trillion, twenty-one billion, six hundred sixty-six million, three hundred eighty-one thousand, two hundred eighty".