21798819840 has 768 divisors, whose sum is σ = 86612198400. Its totient is φ = 4567597056.

The previous prime is 21798819821. The next prime is 21798819851. The reversal of 21798819840 is 4891889712.

It is a tau number, because it is divible by the number of its divisors (768).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 244930516 + ... + 244930604.

It is an arithmetic number, because the mean of its divisors is an integer number (112776300).

Almost surely, 2^21798819840 is an apocalyptic number.

21798819840 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 21798819840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (43306099200).

21798819840 is an abundant number, since it is smaller than the sum of its proper divisors (64813378560).

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

21798819840 is a wasteful number, since it uses less digits than its factorization.

21798819840 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 210 (or 190 counting only the distinct ones).

The product of its (nonzero) digits is 2322432, while the sum is 57.

The spelling of 21798819840 in words is "twenty-one billion, seven hundred ninety-eight million, eight hundred nineteen thousand, eight hundred forty".