21011220013 has 4 divisors (see below), whose sum is σ = 24012822880. Its totient is φ = 18009617148.

The previous prime is 21011219987. The next prime is 21011220019. The reversal of 21011220013 is 31002211012.

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 a de Polignac number, because none of the positive numbers 2^k-21011220013 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21011219975 and 21011220002.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21011220019) 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, 1500801423 + ... + 1500801436.

It is an arithmetic number, because the mean of its divisors is an integer number (6003205720).

Almost surely, 2^21011220013 is an apocalyptic number.

It is an amenable number.

21011220013 is a deficient number, since it is larger than the sum of its proper divisors (3001602867).

21011220013 is an equidigital number, since it uses as much as digits as its factorization.

21011220013 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3001602866.

The product of its (nonzero) digits is 24, while the sum is 13.

Adding to 21011220013 its reverse (31002211012), we get a palindrome (52013431025).

Subtracting 21011220013 from its reverse (31002211012), we obtain a palindrome (9990990999).

The spelling of 21011220013 in words is "twenty-one billion, eleven million, two hundred twenty thousand, thirteen".