221634644 has 72 divisors (see below), whose sum is σ = 521240832. Its totient is φ = 81258240.

The previous prime is 221634641. The next prime is 221634649. The reversal of 221634644 is 446436122.

It is a self number, because there is not a number n which added to its sum of digits gives 221634644.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (221634641) 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, 33629 + ... + 39675.

It is an arithmetic number, because the mean of its divisors is an integer number (7239456).

Almost surely, 2^221634644 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 221634644, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (260620416).

221634644 is an abundant number, since it is smaller than the sum of its proper divisors (299606188).

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

221634644 is a wasteful number, since it uses less digits than its factorization.

221634644 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6093 (or 6084 counting only the distinct ones).

The product of its digits is 27648, while the sum is 32.

The square root of 221634644 is about 14887.3988325698. The cubic root of 221634644 is about 605.1725428231.

The spelling of 221634644 in words is "two hundred twenty-one million, six hundred thirty-four thousand, six hundred forty-four".