21108379838 has 64 divisors (see below), whose sum is σ = 39835017600. Its totient is φ = 8335789056.

The previous prime is 21108379837. The next prime is 21108379913. The reversal of 21108379838 is 83897380112.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21108379837) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 6000056 + ... + 6003572.

It is an arithmetic number, because the mean of its divisors is an integer number (622422150).

Almost surely, 2^21108379838 is an apocalyptic number.

21108379838 is a deficient number, since it is larger than the sum of its proper divisors (18726637762).

21108379838 is a wasteful number, since it uses less digits than its factorization.

21108379838 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4226 (or 4212 counting only the distinct ones).

The product of its (nonzero) digits is 580608, while the sum is 50.

The spelling of 21108379838 in words is "twenty-one billion, one hundred eight million, three hundred seventy-nine thousand, eight hundred thirty-eight".