13220021 has 2 divisors, whose sum is σ = 13220022. Its totient is φ = 13220020.

The previous prime is 13220003. The next prime is 13220023. The reversal of 13220021 is 12002231.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 10817521 + 2402500 = 3289^2 + 1550^2 .

It is an emirp because it is prime and its reverse (12002231) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 13220021 - 2¹⁴ = 13203637 is a prime.

Together with 13220023, it forms a pair of twin primes.

It is a Chen prime.

It is a junction number, because it is equal to n+sod(n) for n = 13219984 and 13220011.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (13220023) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 6610010 + 6610011.

It is an arithmetic number, because the mean of its divisors is an integer number (6610011).

Almost surely, 2^13220021 is an apocalyptic number.

It is an amenable number.

13220021 is a deficient number, since it is larger than the sum of its proper divisors (1).

13220021 is an equidigital number, since it uses as much as digits as its factorization.

13220021 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 24, while the sum is 11.

The square root of 13220021 is about 3635.9346803814. The cubic root of 13220021 is about 236.4525752398.

Adding to 13220021 its reverse (12002231), we get a palindrome (25222252).

The spelling of 13220021 in words is "thirteen million, two hundred twenty thousand, twenty-one".