21220320013 has 8 divisors (see below), whose sum is σ = 21288686328. Its totient is φ = 21152001024.

The previous prime is 21220320001. The next prime is 21220320049. The reversal of 21220320013 is 31002302212.

It can be written as a sum of positive squares in 4 ways, for example, as 5944101604 + 15276218409 = 77098^2 + 123597^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21220320013 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 (21220320613) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1032231 + ... + 1052587.

It is an arithmetic number, because the mean of its divisors is an integer number (2661085791).

Almost surely, 2^21220320013 is an apocalyptic number.

It is an amenable number.

21220320013 is a deficient number, since it is larger than the sum of its proper divisors (68366315).

21220320013 is a wasteful number, since it uses less digits than its factorization.

21220320013 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 23663.

The product of its (nonzero) digits is 144, while the sum is 16.

Adding to 21220320013 its reverse (31002302212), we get a palindrome (52222622225).

The spelling of 21220320013 in words is "twenty-one billion, two hundred twenty million, three hundred twenty thousand, thirteen".