13217021 has 2 divisors, whose sum is σ = 13217022. Its totient is φ = 13217020.

The previous prime is 13216999. The next prime is 13217033. The reversal of 13217021 is 12071231.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 13060996 + 156025 = 3614^2 + 395^2 .

It is a cyclic number.

It is not a de Polignac number, because 13217021 - 2¹⁰ = 13215997 is a prime.

It is a super-4 number, since 4×13217021⁴ (a number of 30 digits) contains 4444 as substring. Note that it is a super-d number also for d = 2.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (13217221) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 6608510 + 6608511.

It is an arithmetic number, because the mean of its divisors is an integer number (6608511).

Almost surely, 2^13217021 is an apocalyptic number.

It is an amenable number.

13217021 is a deficient number, since it is larger than the sum of its proper divisors (1).

13217021 is an equidigital number, since it uses as much as digits as its factorization.

13217021 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 84, while the sum is 17.

The square root of 13217021 is about 3635.5221083085. The cubic root of 13217021 is about 236.4346879412.

Adding to 13217021 its reverse (12071231), we get a palindrome (25288252).

The spelling of 13217021 in words is "thirteen million, two hundred seventeen thousand, twenty-one".