21126010013 has 4 divisors (see below), whose sum is σ = 21472338108. Its totient is φ = 20779681920.

The previous prime is 21126009977. The next prime is 21126010057. The reversal of 21126010013 is 31001062112.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 12100440004 + 9025570009 = 110002^2 + 95003^2 .

It is a cyclic number.

It is not a de Polignac number, because 21126010013 - 2⁸ = 21126009757 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21126009973 and 21126010000.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21126010063) 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, 173163956 + ... + 173164077.

It is an arithmetic number, because the mean of its divisors is an integer number (5368084527).

Almost surely, 2^21126010013 is an apocalyptic number.

It is an amenable number.

21126010013 is a deficient number, since it is larger than the sum of its proper divisors (346328095).

21126010013 is an equidigital number, since it uses as much as digits as its factorization.

21126010013 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 346328094.

The product of its (nonzero) digits is 72, while the sum is 17.

Adding to 21126010013 its reverse (31001062112), we get a palindrome (52127072125).

The spelling of 21126010013 in words is "twenty-one billion, one hundred twenty-six million, ten thousand, thirteen".