221643316 has 6 divisors (see below), whose sum is σ = 387875810. Its totient is φ = 110821656.

The previous prime is 221643313. The next prime is 221643319. The reversal of 221643316 is 613346122.

It is an interprime number because it is at equal distance from previous prime (221643313) and next prime (221643319).

It can be written as a sum of positive squares in only one way, i.e., 120560400 + 101082916 = 10980^2 + 10054^2 .

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (221643313) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 27705411 + ... + 27705418.

Almost surely, 2^221643316 is an apocalyptic number.

It is an amenable number.

221643316 is a deficient number, since it is larger than the sum of its proper divisors (166232494).

221643316 is a wasteful number, since it uses less digits than its factorization.

221643316 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 55410833 (or 55410831 counting only the distinct ones).

The product of its digits is 5184, while the sum is 28.

The square root of 221643316 is about 14887.6900827496. The cubic root of 221643316 is about 605.1804356743.

Adding to 221643316 its reverse (613346122), we get a palindrome (834989438).

The spelling of 221643316 in words is "two hundred twenty-one million, six hundred forty-three thousand, three hundred sixteen".