221165280 has 288 divisors, whose sum is σ = 887350464. Its totient is φ = 49102848.

The previous prime is 221165261. The next prime is 221165299. The reversal of 221165280 is 82561122.

It is a happy number.

221165280 is a `hidden beast` number, since 2 + 2 + 1 + 1 + 652 + 8 + 0 = 666.

It is an interprime number because it is at equal distance from previous prime (221165261) and next prime (221165299).

It is a tau number, because it is divible by the number of its divisors (288).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 372664 + ... + 373256.

It is an arithmetic number, because the mean of its divisors is an integer number (3081078).

Almost surely, 2^221165280 is an apocalyptic number.

221165280 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 221165280, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (443675232).

221165280 is an abundant number, since it is smaller than the sum of its proper divisors (666185184).

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

221165280 is a wasteful number, since it uses less digits than its factorization.

221165280 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 658 (or 647 counting only the distinct ones).

The product of its (nonzero) digits is 1920, while the sum is 27.

The square root of 221165280 is about 14871.6266763256. The cubic root of 221165280 is about 604.7450420373.

It can be divided in two parts, 221165 and 280, that added together give a triangular number (221445 = T₆₆₅).

The spelling of 221165280 in words is "two hundred twenty-one million, one hundred sixty-five thousand, two hundred eighty".