21240004213 has 2 divisors, whose sum is σ = 21240004214. Its totient is φ = 21240004212.

The previous prime is 21240004141. The next prime is 21240004271. The reversal of 21240004213 is 31240004212.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 21239564644 + 439569 = 145738^2 + 663^2 .

It is a cyclic number.

It is not a de Polignac number, because 21240004213 - 2¹³ = 21239996021 is a prime.

It is a super-2 number, since 2×21240004213² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21240004273) 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 as a sum of consecutive naturals, namely, 10620002106 + 10620002107.

It is an arithmetic number, because the mean of its divisors is an integer number (10620002107).

Almost surely, 2^21240004213 is an apocalyptic number.

It is an amenable number.

21240004213 is a deficient number, since it is larger than the sum of its proper divisors (1).

21240004213 is an equidigital number, since it uses as much as digits as its factorization.

21240004213 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 384, while the sum is 19.

Adding to 21240004213 its reverse (31240004212), we get a palindrome (52480008425).

Subtracting 21240004213 from its reverse (31240004212), we obtain a palindrome (9999999999).

The spelling of 21240004213 in words is "twenty-one billion, two hundred forty million, four thousand, two hundred thirteen".