21105044880 has 80 divisors (see below), whose sum is σ = 65464143360. Its totient is φ = 5624699904.

The previous prime is 21105044879. The next prime is 21105044899. The reversal of 21105044880 is 8844050112.

It is a tau number, because it is divible by the number of its divisors (80).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 397164 + ... + 447156.

It is an arithmetic number, because the mean of its divisors is an integer number (818301792).

Almost surely, 2^21105044880 is an apocalyptic number.

21105044880 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21105044880 is an abundant number, since it is smaller than the sum of its proper divisors (44359098480).

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

21105044880 is a wasteful number, since it uses less digits than its factorization.

21105044880 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 51768 (or 51762 counting only the distinct ones).

The product of its (nonzero) digits is 10240, while the sum is 33.

Adding to 21105044880 its reverse (8844050112), we get a palindrome (29949094992).

The spelling of 21105044880 in words is "twenty-one billion, one hundred five million, forty-four thousand, eight hundred eighty".