21240443213 has 12 divisors (see below), whose sum is σ = 24362020704. Its totient is φ = 18469948200.

The previous prime is 21240443201. The next prime is 21240443239. The reversal of 21240443213 is 31234404212.

It is not a de Polignac number, because 21240443213 - 2¹⁸ = 21240181069 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21240443243) 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 11 ways as a sum of consecutive naturals, for example, 3813323 + ... + 3818888.

It is an arithmetic number, because the mean of its divisors is an integer number (2030168392).

Almost surely, 2^21240443213 is an apocalyptic number.

21240443213 is a gapful number since it is divisible by the number (23) formed by its first and last digit.

It is an amenable number.

21240443213 is a deficient number, since it is larger than the sum of its proper divisors (3121577491).

21240443213 is a wasteful number, since it uses less digits than its factorization.

21240443213 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7632256 (or 7632245 counting only the distinct ones).

The product of its (nonzero) digits is 4608, while the sum is 26.

Adding to 21240443213 its reverse (31234404212), we get a palindrome (52474847425).

The spelling of 21240443213 in words is "twenty-one billion, two hundred forty million, four hundred forty-three thousand, two hundred thirteen".