21311321012 has 12 divisors (see below), whose sum is σ = 37422099876. Its totient is φ = 10619292480.

The previous prime is 21311321011. The next prime is 21311321069. The reversal of 21311321012 is 21012311312.

It can be written as a sum of positive squares in 2 ways, for example, as 20965881616 + 345439396 = 144796^2 + 18586^2 .

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21311321011) 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, 9090689 + ... + 9093032.

It is an arithmetic number, because the mean of its divisors is an integer number (3118508323).

Almost surely, 2^21311321012 is an apocalyptic number.

It is an amenable number.

21311321012 is a deficient number, since it is larger than the sum of its proper divisors (16110778864).

21311321012 is a wasteful number, since it uses less digits than its factorization.

21311321012 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18184018 (or 18184016 counting only the distinct ones).

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

Adding to 21311321012 its reverse (21012311312), we get a palindrome (42323632324).

The spelling of 21311321012 in words is "twenty-one billion, three hundred eleven million, three hundred twenty-one thousand, twelve".