221604144 has 80 divisors (see below), whose sum is σ = 606211200. Its totient is φ = 69562368.

The previous prime is 221604143. The next prime is 221604199. The reversal of 221604144 is 441406122.

It is a happy number.

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

It is not an unprimeable number, because it can be changed into a prime (221604143) 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 15 ways as a sum of consecutive naturals, for example, 175387 + ... + 176645.

It is an arithmetic number, because the mean of its divisors is an integer number (7577640).

Almost surely, 2^221604144 is an apocalyptic number.

221604144 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 221604144, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (303105600).

221604144 is an abundant number, since it is smaller than the sum of its proper divisors (384607056).

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

221604144 is a wasteful number, since it uses less digits than its factorization.

221604144 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1482 (or 1476 counting only the distinct ones).

The product of its (nonzero) digits is 1536, while the sum is 24.

The square root of 221604144 is about 14886.3744410787. The cubic root of 221604144 is about 605.1447815054.

The spelling of 221604144 in words is "two hundred twenty-one million, six hundred four thousand, one hundred forty-four".