221306004 has 18 divisors (see below), whose sum is σ = 559412490. Its totient is φ = 73768656.

The previous prime is 221306003. The next prime is 221306021. The reversal of 221306004 is 400603122.

It is a happy number.

221306004 is digitally balanced in base 3 and base 9, because in such bases it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in only one way, i.e., 217503504 + 3802500 = 14748^2 + 1950^2 .

It is a tau number, because it is divible by the number of its divisors (18).

It is a Harshad number since it is a multiple of its sum of digits (18).

221306004 is strictly pandigital in base 9.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (221306003) 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 5 ways as a sum of consecutive naturals, for example, 3073659 + ... + 3073730.

Almost surely, 2^221306004 is an apocalyptic number.

It is an amenable number.

221306004 is an abundant number, since it is smaller than the sum of its proper divisors (338106486).

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

221306004 is a wasteful number, since it uses less digits than its factorization.

221306004 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6147399 (or 6147394 counting only the distinct ones).

The product of its (nonzero) digits is 288, while the sum is 18.

The square root of 221306004 is about 14876.3572153938. The cubic root of 221306004 is about 604.8732781057.

Adding to 221306004 its reverse (400603122), we get a palindrome (621909126).

The spelling of 221306004 in words is "two hundred twenty-one million, three hundred six thousand, four".