221866320 has 320 divisors, whose sum is σ = 809948160. Its totient is φ = 49741824.

The previous prime is 221866297. The next prime is 221866331. The reversal of 221866320 is 23668122.

It is a Harshad number since it is a multiple of its sum of digits (30).

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 63 ways as a sum of consecutive naturals, for example, 2492836 + ... + 2492924.

It is an arithmetic number, because the mean of its divisors is an integer number (2531088).

Almost surely, 2^221866320 is an apocalyptic number.

221866320 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 221866320, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (404974080).

221866320 is an abundant number, since it is smaller than the sum of its proper divisors (588081840).

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

221866320 is a wasteful number, since it uses less digits than its factorization.

221866320 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 182 (or 176 counting only the distinct ones).

The product of its (nonzero) digits is 6912, while the sum is 30.

The square root of 221866320 is about 14895.1777431490. The cubic root of 221866320 is about 605.3833328690.

The spelling of 221866320 in words is "two hundred twenty-one million, eight hundred sixty-six thousand, three hundred twenty".