221215345 has 8 divisors (see below), whose sum is σ = 285878376. Its totient is φ = 163358976.

The previous prime is 221215343. The next prime is 221215361. The reversal of 221215345 is 543512122.

It can be written as a sum of positive squares in 4 ways, for example, as 33744481 + 187470864 = 5809^2 + 13692^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 221215345 - 2¹ = 221215343 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (221215343) 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 7 ways as a sum of consecutive naturals, for example, 1701592 + ... + 1701721.

It is an arithmetic number, because the mean of its divisors is an integer number (35734797).

Almost surely, 2^221215345 is an apocalyptic number.

It is an amenable number.

221215345 is a deficient number, since it is larger than the sum of its proper divisors (64663031).

221215345 is a wasteful number, since it uses less digits than its factorization.

221215345 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3403331.

The product of its digits is 2400, while the sum is 25.

The square root of 221215345 is about 14873.3098199426. The cubic root of 221215345 is about 604.7906704715.

Adding to 221215345 its reverse (543512122), we get a palindrome (764727467).

The spelling of 221215345 in words is "two hundred twenty-one million, two hundred fifteen thousand, three hundred forty-five".