21000244013 has 4 divisors (see below), whose sum is σ = 24000278880. Its totient is φ = 18000209148.

The previous prime is 21000244009. The next prime is 21000244043. The reversal of 21000244013 is 31044200012.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 21000244013 - 2² = 21000244009 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21000243982 and 21000244000.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21000244003) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1500017423 + ... + 1500017436.

It is an arithmetic number, because the mean of its divisors is an integer number (6000069720).

Almost surely, 2^21000244013 is an apocalyptic number.

It is an amenable number.

21000244013 is a deficient number, since it is larger than the sum of its proper divisors (3000034867).

21000244013 is an equidigital number, since it uses as much as digits as its factorization.

21000244013 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3000034866.

The product of its (nonzero) digits is 192, while the sum is 17.

Adding to 21000244013 its reverse (31044200012), we get a palindrome (52044444025).

The spelling of 21000244013 in words is "twenty-one billion, two hundred forty-four thousand, thirteen".