20305213 has 2 divisors, whose sum is σ = 20305214. Its totient is φ = 20305212.

The previous prime is 20305211. The next prime is 20305231. The reversal of 20305213 is 31250302.

Together with next prime (20305231) it forms an Ormiston pair, because they use the same digits, order apart.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 16216729 + 4088484 = 4027^2 + 2022^2 .

It is a cyclic number.

It is not a de Polignac number, because 20305213 - 2¹ = 20305211 is a prime.

Together with 20305211, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20305211) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10152606 + 10152607.

It is an arithmetic number, because the mean of its divisors is an integer number (10152607).

Almost surely, 2^20305213 is an apocalyptic number.

It is an amenable number.

20305213 is a deficient number, since it is larger than the sum of its proper divisors (1).

20305213 is an equidigital number, since it uses as much as digits as its factorization.

20305213 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 180, while the sum is 16.

The square root of 20305213 is about 4506.1306017469. The cubic root of 20305213 is about 272.8155892528.

Adding to 20305213 its reverse (31250302), we get a palindrome (51555515).

The spelling of 20305213 in words is "twenty million, three hundred five thousand, two hundred thirteen".