16221617 has 2 divisors, whose sum is σ = 16221618. Its totient is φ = 16221616.

The previous prime is 16221613. The next prime is 16221619. The reversal of 16221617 is 71612261.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 12967201 + 3254416 = 3601^2 + 1804^2 .

It is a cyclic number.

It is not a de Polignac number, because 16221617 - 2² = 16221613 is a prime.

Together with 16221619, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (16221613) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 8110808 + 8110809.

It is an arithmetic number, because the mean of its divisors is an integer number (8110809).

Almost surely, 2^16221617 is an apocalyptic number.

It is an amenable number.

16221617 is a deficient number, since it is larger than the sum of its proper divisors (1).

16221617 is an equidigital number, since it uses as much as digits as its factorization.

16221617 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1008, while the sum is 26.

The square root of 16221617 is about 4027.6068576762. The cubic root of 16221617 is about 253.1422957648.

Adding to 16221617 its reverse (71612261), we get a palindrome (87833878).

The spelling of 16221617 in words is "sixteen million, two hundred twenty-one thousand, six hundred seventeen".