21001320013 has 16 divisors (see below), whose sum is σ = 21918314880. Its totient is φ = 20104628544.

The previous prime is 21001320007. The next prime is 21001320017. The reversal of 21001320013 is 31002310012.

It is a cyclic number.

It is not a de Polignac number, because 21001320013 - 2⁹ = 21001319501 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21001319975 and 21001320002.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21001320017) 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 15 ways as a sum of consecutive naturals, for example, 2418243 + ... + 2426911.

It is an arithmetic number, because the mean of its divisors is an integer number (1369894680).

Almost surely, 2^21001320013 is an apocalyptic number.

It is an amenable number.

21001320013 is a deficient number, since it is larger than the sum of its proper divisors (916994867).

21001320013 is a wasteful number, since it uses less digits than its factorization.

21001320013 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9828.

The product of its (nonzero) digits is 36, while the sum is 13.

Adding to 21001320013 its reverse (31002310012), we get a palindrome (52003630025).

The spelling of 21001320013 in words is "twenty-one billion, one million, three hundred twenty thousand, thirteen".