21090885984 has 288 divisors, whose sum is σ = 72924074496. Its totient is φ = 5644431360.

The previous prime is 21090885971. The next prime is 21090886007. The reversal of 21090885984 is 48958809012.

It is a tau number, because it is divible by the number of its divisors (288).

It is a self number, because there is not a number n which added to its sum of digits gives 21090885984.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 7778389 + ... + 7781099.

It is an arithmetic number, because the mean of its divisors is an integer number (253208592).

Almost surely, 2^21090885984 is an apocalyptic number.

21090885984 is a gapful number since it is divisible by the number (24) 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 21090885984, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (36462037248).

21090885984 is an abundant number, since it is smaller than the sum of its proper divisors (51833188512).

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

21090885984 is a wasteful number, since it uses less digits than its factorization.

21090885984 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2978 (or 2967 counting only the distinct ones).

The product of its (nonzero) digits is 1658880, while the sum is 54.

The spelling of 21090885984 in words is "twenty-one billion, ninety million, eight hundred eighty-five thousand, nine hundred eighty-four".