21091107321984 has 128 divisors (see below), whose sum is σ = 64232451578880. Its totient is φ = 6006654120960.

The previous prime is 21091107321967. The next prime is 21091107321997. The reversal of 21091107321984 is 48912370119012.

It is a tau number, because it is divible by the number of its divisors (128).

It is a Harshad number since it is a multiple of its sum of digits (48).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 11778814 + ... + 13450749.

It is an arithmetic number, because the mean of its divisors is an integer number (501816027960).

Almost surely, 2^{21091107321984} is an apocalyptic number.

21091107321984 is a gapful number since it is divisible by the number (24) formed by its first and last digit.

It is an amenable number.

21091107321984 is an abundant number, since it is smaller than the sum of its proper divisors (43141344256896).

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

21091107321984 is a wasteful number, since it uses less digits than its factorization.

21091107321984 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 25229898 (or 25229886 counting only the distinct ones).

The product of its (nonzero) digits is 217728, while the sum is 48.

The spelling of 21091107321984 in words is "twenty-one trillion, ninety-one billion, one hundred seven million, three hundred twenty-one thousand, nine hundred eighty-four".