1668221280 has 576 divisors, whose sum is σ = 6849722880. Its totient is φ = 364953600.

The previous prime is 1668221221. The next prime is 1668221281. The reversal of 1668221280 is 821228661.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1668221281) by changing a digit.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 6921960 + ... + 6922200.

It is an arithmetic number, because the mean of its divisors is an integer number (11891880).

Almost surely, 2^1668221280 is an apocalyptic number.

1668221280 is a gapful number since it is divisible by the number (10) 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 1668221280, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (3424861440).

1668221280 is an abundant number, since it is smaller than the sum of its proper divisors (5181501600).

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

1668221280 is a wasteful number, since it uses less digits than its factorization.

1668221280 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 315 (or 304 counting only the distinct ones).

The product of its (nonzero) digits is 18432, while the sum is 36.

The square root of 1668221280 is about 40843.8646555391. The cubic root of 1668221280 is about 1185.9996265214. Note that the first 3 decimals are identical.

The spelling of 1668221280 in words is "one billion, six hundred sixty-eight million, two hundred twenty-one thousand, two hundred eighty".