21984687648 has 288 divisors, whose sum is σ = 79049198592. Its totient is φ = 5629478400.

The previous prime is 21984687581. The next prime is 21984687727. The reversal of 21984687648 is 84678648912.

21984687648 is a `hidden beast` number, since 21 + 98 + 468 + 7 + 64 + 8 = 666.

It is a tau number, because it is divible by the number of its divisors (288).

It is a Harshad number since it is a multiple of its sum of digits (63).

It is a nude number because it is divisible by every one of its digits.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 1567515 + ... + 1581477.

It is an arithmetic number, because the mean of its divisors is an integer number (274476384).

Almost surely, 2^21984687648 is an apocalyptic number.

21984687648 is a gapful number since it is divisible by the number (28) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21984687648, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (39524599296).

21984687648 is an abundant number, since it is smaller than the sum of its proper divisors (57064510944).

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

21984687648 is a wasteful number, since it uses less digits than its factorization.

21984687648 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 14068 (or 14057 counting only the distinct ones).

The product of its digits is 37158912, while the sum is 63.

The spelling of 21984687648 in words is "twenty-one billion, nine hundred eighty-four million, six hundred eighty-seven thousand, six hundred forty-eight".