221378544 has 60 divisors (see below), whose sum is σ = 621870912. Its totient is φ = 73516800.

The previous prime is 221378543. The next prime is 221378551. The reversal of 221378544 is 445873122.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a junction number, because it is equal to n+sod(n) for n = 221378499 and 221378508.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (221378543) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 37729 + ... + 43199.

Almost surely, 2^221378544 is an apocalyptic number.

221378544 is a gapful number since it is divisible by the number (24) 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 221378544, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (310935456).

221378544 is an abundant number, since it is smaller than the sum of its proper divisors (400492368).

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

221378544 is a wasteful number, since it uses less digits than its factorization.

221378544 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5766 (or 5757 counting only the distinct ones).

The product of its digits is 53760, while the sum is 36.

The square root of 221378544 is about 14878.7951125083. The cubic root of 221378544 is about 604.9393596303.

The spelling of 221378544 in words is "two hundred twenty-one million, three hundred seventy-eight thousand, five hundred forty-four".