21944281408 has 56 divisors (see below), whose sum is σ = 49928914112. Its totient is φ = 9373999104.

The previous prime is 21944281391. The next prime is 21944281409. The reversal of 21944281408 is 80418244912.

It is a tau number, because it is divible by the number of its divisors (56).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21944281409) 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, 57760 + ... + 217312.

It is an arithmetic number, because the mean of its divisors is an integer number (891587752).

Almost surely, 2^21944281408 is an apocalyptic number.

21944281408 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 21944281408, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (24964457056).

21944281408 is an abundant number, since it is smaller than the sum of its proper divisors (27984632704).

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

21944281408 is a wasteful number, since it uses less digits than its factorization.

21944281408 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 159879 (or 159869 counting only the distinct ones).

The product of its (nonzero) digits is 147456, while the sum is 43.

The spelling of 21944281408 in words is "twenty-one billion, nine hundred forty-four million, two hundred eighty-one thousand, four hundred eight".