221921280 has 360 divisors, whose sum is σ = 899650752. Its totient is φ = 49545216.

The previous prime is 221921279. The next prime is 221921291. The reversal of 221921280 is 82129122.

It is a tau number, because it is divible by the number of its divisors (360).

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 5160939 + ... + 5160981.

Almost surely, 2^221921280 is an apocalyptic number.

221921280 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 221921280, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (449825376).

221921280 is an abundant number, since it is smaller than the sum of its proper divisors (677729472).

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

221921280 is an equidigital number, since it uses as much as digits as its factorization.

221921280 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 89 (or 60 counting only the distinct ones).

The product of its (nonzero) digits is 1152, while the sum is 27.

The square root of 221921280 is about 14897.0225212960. The cubic root of 221921280 is about 605.4333166025.

The spelling of 221921280 in words is "two hundred twenty-one million, nine hundred twenty-one thousand, two hundred eighty".