21101042242013 has 4 divisors (see below), whose sum is σ = 21101081519868. Its totient is φ = 21101002964160.

The previous prime is 21101042242009. The next prime is 21101042242069. The reversal of 21101042242013 is 31024224010112.

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 13074031334809 + 8027010907204 = 3615803^2 + 2833198^2 .

It is a cyclic number.

It is not a de Polignac number, because 21101042242013 - 2² = 21101042242009 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21101042242013.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21101042242003) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 18821756 + ... + 19911317.

It is an arithmetic number, because the mean of its divisors is an integer number (5275270379967).

Almost surely, 2^{21101042242013} is an apocalyptic number.

It is an amenable number.

21101042242013 is a deficient number, since it is larger than the sum of its proper divisors (39277855).

21101042242013 is an equidigital number, since it uses as much as digits as its factorization.

21101042242013 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 39277854.

The product of its (nonzero) digits is 768, while the sum is 23.

Adding to 21101042242013 its reverse (31024224010112), we get a palindrome (52125266252125).

The spelling of 21101042242013 in words is "twenty-one trillion, one hundred one billion, forty-two million, two hundred forty-two thousand, thirteen".