213243020405 has 4 divisors (see below), whose sum is σ = 255891624492. Its totient is φ = 170594416320.

The previous prime is 213243020401. The next prime is 213243020447. The reversal of 213243020405 is 504020342312.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 68190965956 + 145052054449 = 261134^2 + 380857^2 .

It is not a de Polignac number, because 213243020405 - 2² = 213243020401 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (213243020401) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 21324302036 + ... + 21324302045.

It is an arithmetic number, because the mean of its divisors is an integer number (63972906123).

Almost surely, 2^213243020405 is an apocalyptic number.

It is an amenable number.

213243020405 is a deficient number, since it is larger than the sum of its proper divisors (42648604087).

213243020405 is an equidigital number, since it uses as much as digits as its factorization.

213243020405 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 42648604086.

The product of its (nonzero) digits is 5760, while the sum is 26.

Adding to 213243020405 its reverse (504020342312), we get a palindrome (717263362717).

The spelling of 213243020405 in words is "two hundred thirteen billion, two hundred forty-three million, twenty thousand, four hundred five".