221320305 has 48 divisors (see below), whose sum is σ = 393765840. Its totient is φ = 114960384.

The previous prime is 221320301. The next prime is 221320313. The reversal of 221320305 is 503023122.

It can be written as a sum of positive squares in 8 ways, for example, as 4524129 + 216796176 = 2127^2 + 14724^2 .

It is not a de Polignac number, because 221320305 - 2² = 221320301 is a prime.

It is not an unprimeable number, because it can be changed into a prime (221320301) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 291987 + ... + 292743.

It is an arithmetic number, because the mean of its divisors is an integer number (8203455).

Almost surely, 2^221320305 is an apocalyptic number.

It is an amenable number.

221320305 is a deficient number, since it is larger than the sum of its proper divisors (172445535).

221320305 is a wasteful number, since it uses less digits than its factorization.

221320305 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 930 (or 927 counting only the distinct ones).

The product of its (nonzero) digits is 360, while the sum is 18.

The square root of 221320305 is about 14876.8378696550. The cubic root of 221320305 is about 604.8863069832.

Adding to 221320305 its reverse (503023122), we get a palindrome (724343427).

The spelling of 221320305 in words is "two hundred twenty-one million, three hundred twenty thousand, three hundred five".