616224221 has 2 divisors, whose sum is σ = 616224222. Its totient is φ = 616224220.

The previous prime is 616224209. The next prime is 616224223. The reversal of 616224221 is 122422616.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 575328196 + 40896025 = 23986^2 + 6395^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-616224221 is a prime.

It is a Sophie Germain prime.

Together with 616224223, it forms a pair of twin primes.

It is a Chen prime.

It is a Curzon number.

It is equal to p_32127092 and since 616224221 and 32127092 have the same sum of digits, it is a Honaker prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (616224223) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 308112110 + 308112111.

It is an arithmetic number, because the mean of its divisors is an integer number (308112111).

Almost surely, 2^616224221 is an apocalyptic number.

It is an amenable number.

616224221 is a deficient number, since it is larger than the sum of its proper divisors (1).

616224221 is an equidigital number, since it uses as much as digits as its factorization.

616224221 is an evil number, because the sum of its binary digits is even.

The product of its digits is 2304, while the sum is 26.

The square root of 616224221 is about 24823.8639417799. The cubic root of 616224221 is about 850.9673973047.

Adding to 616224221 its reverse (122422616), we get a palindrome (738646837).

The spelling of 616224221 in words is "six hundred sixteen million, two hundred twenty-four thousand, two hundred twenty-one".