16221313 has 2 divisors, whose sum is σ = 16221314. Its totient is φ = 16221312.

The previous prime is 16221311. The next prime is 16221323. The reversal of 16221313 is 31312261.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 11675889 + 4545424 = 3417^2 + 2132^2 .

It is a cyclic number.

It is not a de Polignac number, because 16221313 - 2¹ = 16221311 is a prime.

It is a super-3 number, since 3×16221313³ (a number of 23 digits) contains 333 as substring.

Together with 16221311, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (16221311) 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, 8110656 + 8110657.

It is an arithmetic number, because the mean of its divisors is an integer number (8110657).

Almost surely, 2^16221313 is an apocalyptic number.

It is an amenable number.

16221313 is a deficient number, since it is larger than the sum of its proper divisors (1).

16221313 is an equidigital number, since it uses as much as digits as its factorization.

16221313 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 216, while the sum is 19.

The square root of 16221313 is about 4027.5691179668. The cubic root of 16221313 is about 253.1407144235.

Adding to 16221313 its reverse (31312261), we get a palindrome (47533574).

The spelling of 16221313 in words is "sixteen million, two hundred twenty-one thousand, three hundred thirteen".