221649218 has 8 divisors (see below), whose sum is σ = 379970112. Its totient is φ = 94992516.

The previous prime is 221649187. The next prime is 221649223. The reversal of 221649218 is 812946122.

221649218 is digitally balanced in base 3, because in such base it contains all the possibile digits an equal number of times.

It is a sphenic number, since it is the product of 3 distinct primes.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 7916030 + ... + 7916057.

It is an arithmetic number, because the mean of its divisors is an integer number (47496264).

Almost surely, 2^221649218 is an apocalyptic number.

221649218 is a deficient number, since it is larger than the sum of its proper divisors (158320894).

221649218 is a wasteful number, since it uses less digits than its factorization.

221649218 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 15832096.

The product of its digits is 13824, while the sum is 35.

The square root of 221649218 is about 14887.8882988824. Note that the first 3 decimals coincide. The cubic root of 221649218 is about 605.1858072827.

The spelling of 221649218 in words is "two hundred twenty-one million, six hundred forty-nine thousand, two hundred eighteen".