21784874388 has 48 divisors (see below), whose sum is σ = 51266525184. Its totient is φ = 7199539200.

The previous prime is 21784874323. The next prime is 21784874389. The reversal of 21784874388 is 88347848712.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21784874389) 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 15 ways as a sum of consecutive naturals, for example, 2740756 + ... + 2748692.

It is an arithmetic number, because the mean of its divisors is an integer number (1068052608).

Almost surely, 2^21784874388 is an apocalyptic number.

It is an amenable number.

21784874388 is an abundant number, since it is smaller than the sum of its proper divisors (29481650796).

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

21784874388 is a wasteful number, since it uses less digits than its factorization.

21784874388 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9872 (or 9870 counting only the distinct ones).

The product of its digits is 19267584, while the sum is 60.

The spelling of 21784874388 in words is "twenty-one billion, seven hundred eighty-four million, eight hundred seventy-four thousand, three hundred eighty-eight".