21021111013 has 16 divisors (see below), whose sum is σ = 24903694080. Its totient is φ = 17360977536.

The previous prime is 21021110989. The next prime is 21021111029. The reversal of 21021111013 is 31011112012.

It is a happy number.

It is a de Polignac number, because none of the positive numbers 2^k-21021111013 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21021110984 and 21021111002.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21021115013) 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, 7456 + ... + 205177.

It is an arithmetic number, because the mean of its divisors is an integer number (1556480880).

Almost surely, 2^21021111013 is an apocalyptic number.

It is an amenable number.

21021111013 is a deficient number, since it is larger than the sum of its proper divisors (3882583067).

21021111013 is a wasteful number, since it uses less digits than its factorization.

21021111013 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 213156.

The product of its (nonzero) digits is 12, while the sum is 13.

Adding to 21021111013 its reverse (31011112012), we get a palindrome (52032223025).

Subtracting 21021111013 from its reverse (31011112012), we obtain a palindrome (9990000999).

The spelling of 21021111013 in words is "twenty-one billion, twenty-one million, one hundred eleven thousand, thirteen".