21947533608 has 256 divisors, whose sum is σ = 75664189440. Its totient is φ = 5119718400.

The previous prime is 21947533541. The next prime is 21947533627. The reversal of 21947533608 is 80633574912.

It is a Cunningham number, because it is equal to 148147²-1.

It is an unprimeable number.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 876543 + ... + 901233.

It is an arithmetic number, because the mean of its divisors is an integer number (295563240).

It is a 2-persistent number, because it is pandigital, and so is 2⋅21947533608 = 43895067216, but 3⋅21947533608 = 65842600824 is not.

Almost surely, 2^21947533608 is an apocalyptic number.

21947533608 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 21947533608, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (37832094720).

21947533608 is an abundant number, since it is smaller than the sum of its proper divisors (53716655832).

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

21947533608 is a wasteful number, since it uses less digits than its factorization.

21947533608 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 24768 (or 24764 counting only the distinct ones).

The product of its (nonzero) digits is 1088640, while the sum is 48.

It can be divided in two parts, 21947 and 533608, that added together give a palindrome (555555).

The spelling of 21947533608 in words is "twenty-one billion, nine hundred forty-seven million, five hundred thirty-three thousand, six hundred eight".