21382811988 has 24 divisors (see below), whose sum is σ = 49896782208. Its totient is φ = 7127096256.

The previous prime is 21382811981. The next prime is 21382811993. The reversal of 21382811988 is 88911828312.

It is a self number, because there is not a number n which added to its sum of digits gives 21382811988.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21382811981) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 137445 + ... + 248307.

It is an arithmetic number, because the mean of its divisors is an integer number (2079032592).

Almost surely, 2^21382811988 is an apocalyptic number.

It is an amenable number.

21382811988 is an abundant number, since it is smaller than the sum of its proper divisors (28513970220).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21382811988 is a wasteful number, since it uses less digits than its factorization.

21382811988 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 126943 (or 126941 counting only the distinct ones).

The product of its digits is 442368, while the sum is 51.

The spelling of 21382811988 in words is "twenty-one billion, three hundred eighty-two million, eight hundred eleven thousand, nine hundred eighty-eight".