221564928 has 208 divisors, whose sum is σ = 678870080. Its totient is φ = 63700992.

The previous prime is 221564899. The next prime is 221564929. The reversal of 221564928 is 829465122.

It is a tau number, because it is divible by the number of its divisors (208).

It is a Harshad number since it is a multiple of its sum of digits (39).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (221564929) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 3035100 + ... + 3035172.

Almost surely, 2^221564928 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 221564928, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (339435040).

221564928 is an abundant number, since it is smaller than the sum of its proper divisors (457305152).

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

221564928 is a wasteful number, since it uses less digits than its factorization.

221564928 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 132 (or 110 counting only the distinct ones).

The product of its digits is 69120, while the sum is 39.

The square root of 221564928 is about 14885.0572051303. The cubic root of 221564928 is about 605.1090830788.

The spelling of 221564928 in words is "two hundred twenty-one million, five hundred sixty-four thousand, nine hundred twenty-eight".