21020305013 has 4 divisors (see below), whose sum is σ = 21108256320. Its totient is φ = 20932353708.

The previous prime is 21020304997. The next prime is 21020305039. The reversal of 21020305013 is 31050302012.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 21020305013 - 2⁴ = 21020304997 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21020304982 and 21020305000.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21020305073) 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, 43975295 + ... + 43975772.

It is an arithmetic number, because the mean of its divisors is an integer number (5277064080).

Almost surely, 2^21020305013 is an apocalyptic number.

It is an amenable number.

21020305013 is a deficient number, since it is larger than the sum of its proper divisors (87951307).

21020305013 is an equidigital number, since it uses as much as digits as its factorization.

21020305013 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 87951306.

The product of its (nonzero) digits is 180, while the sum is 17.

Adding to 21020305013 its reverse (31050302012), we get a palindrome (52070607025).

The spelling of 21020305013 in words is "twenty-one billion, twenty million, three hundred five thousand, thirteen".