21643886880 has 1440 divisors, whose sum is σ = 101981835648. Its totient is φ = 4196966400.

The previous prime is 21643886863. The next prime is 21643886881. The reversal of 21643886880 is 8868834612.

It is a tau number, because it is divible by the number of its divisors (1440).

It is a super-2 number, since 2×21643886880² (a number of 21 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (54).

It is not an unprimeable number, because it can be changed into a prime (21643886881) by changing a digit.

It is a polite number, since it can be written in 239 ways as a sum of consecutive naturals, for example, 527899660 + ... + 527899700.

Almost surely, 2^21643886880 is an apocalyptic number.

21643886880 is a gapful number since it is divisible by the number (20) 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 21643886880, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (50990917824).

21643886880 is an abundant number, since it is smaller than the sum of its proper divisors (80337948768).

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

21643886880 is a wasteful number, since it uses less digits than its factorization.

21643886880 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 132 (or 92 counting only the distinct ones).

The product of its (nonzero) digits is 3538944, while the sum is 54.

The spelling of 21643886880 in words is "twenty-one billion, six hundred forty-three million, eight hundred eighty-six thousand, eight hundred eighty".