221009208 has 96 divisors (see below), whose sum is σ = 670757760. Its totient is φ = 60392640.

The previous prime is 221009171. The next prime is 221009209. The reversal of 221009208 is 802900122.

It is a Harshad number since it is a multiple of its sum of digits (24).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (221009209) by changing a digit.

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 23 ways as a sum of consecutive naturals, for example, 22963 + ... + 31133.

It is an arithmetic number, because the mean of its divisors is an integer number (6987060).

Almost surely, 2^221009208 is an apocalyptic number.

221009208 is a gapful number since it is divisible by the number (28) 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 221009208, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (335378880).

221009208 is an abundant number, since it is smaller than the sum of its proper divisors (449748552).

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

221009208 is a wasteful number, since it uses less digits than its factorization.

221009208 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8217 (or 8206 counting only the distinct ones).

The product of its (nonzero) digits is 576, while the sum is 24.

The square root of 221009208 is about 14866.3784426470. The cubic root of 221009208 is about 604.6027563245.

The spelling of 221009208 in words is "two hundred twenty-one million, nine thousand, two hundred eight".