21311966938 has 16 divisors (see below), whose sum is σ = 34256234880. Its totient is φ = 9908326336.

The previous prime is 21311966933. The next prime is 21311966939. The reversal of 21311966938 is 83966911312.

It is a junction number, because it is equal to n+sod(n) for n = 21311966891 and 21311966900.

It is not an unprimeable number, because it can be changed into a prime (21311966933) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 3773218 + ... + 3778861.

It is an arithmetic number, because the mean of its divisors is an integer number (2141014680).

Almost surely, 2^21311966938 is an apocalyptic number.

21311966938 is a deficient number, since it is larger than the sum of its proper divisors (12944267942).

21311966938 is a wasteful number, since it uses less digits than its factorization.

21311966938 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7552181.

The product of its digits is 419904, while the sum is 49.

The spelling of 21311966938 in words is "twenty-one billion, three hundred eleven million, nine hundred sixty-six thousand, nine hundred thirty-eight".