21311222013 has 16 divisors (see below), whose sum is σ = 31952571840. Its totient is φ = 14036305392.

The previous prime is 21311222011. The next prime is 21311222029. The reversal of 21311222013 is 31022211312.

It is not a de Polignac number, because 21311222013 - 2¹ = 21311222011 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21311222011) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 4752606 + ... + 4757087.

It is an arithmetic number, because the mean of its divisors is an integer number (1997035740).

Almost surely, 2^21311222013 is an apocalyptic number.

It is an amenable number.

21311222013 is a deficient number, since it is larger than the sum of its proper divisors (10641349827).

21311222013 is an equidigital number, since it uses as much as digits as its factorization.

21311222013 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9509785 (or 9509779 counting only the distinct ones).

The product of its (nonzero) digits is 144, while the sum is 18.

Adding to 21311222013 its reverse (31022211312), we get a palindrome (52333433325).

The spelling of 21311222013 in words is "twenty-one billion, three hundred eleven million, two hundred twenty-two thousand, thirteen".