21056593920 has 224 divisors, whose sum is σ = 67707662400. Its totient is φ = 5587599360.

The previous prime is 21056593897. The next prime is 21056593931. The reversal of 21056593920 is 2939565012.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 42884875 + ... + 42885365.

It is an arithmetic number, because the mean of its divisors is an integer number (302266350).

Almost surely, 2^21056593920 is an apocalyptic number.

21056593920 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 21056593920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (33853831200).

21056593920 is an abundant number, since it is smaller than the sum of its proper divisors (46651068480).

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

21056593920 is an equidigital number, since it uses as much as digits as its factorization.

21056593920 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 874 (or 850 counting only the distinct ones).

The product of its (nonzero) digits is 145800, while the sum is 42.

The spelling of 21056593920 in words is "twenty-one billion, fifty-six million, five hundred ninety-three thousand, nine hundred twenty".