21816839788 has 12 divisors (see below), whose sum is σ = 38180512440. Its totient is φ = 10908121952.

The previous prime is 21816839783. The next prime is 21816839797. The reversal of 21816839788 is 88793861812.

It is not an unprimeable number, because it can be changed into a prime (21816839783) 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, 217083 + ... + 301261.

It is an arithmetic number, because the mean of its divisors is an integer number (3181709370).

Almost surely, 2^21816839788 is an apocalyptic number.

It is an amenable number.

21816839788 is a deficient number, since it is larger than the sum of its proper divisors (16363672652).

21816839788 is a wasteful number, since it uses less digits than its factorization.

21816839788 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 148976 (or 148974 counting only the distinct ones).

The product of its digits is 9289728, while the sum is 61.

The spelling of 21816839788 in words is "twenty-one billion, eight hundred sixteen million, eight hundred thirty-nine thousand, seven hundred eighty-eight".