21138569760 has 576 divisors, whose sum is σ = 88232094720. Its totient is φ = 4131962880.

The previous prime is 21138569723. The next prime is 21138569779. The reversal of 21138569760 is 6796583112.

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 (19) of ones.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 10680451 + ... + 10682429.

It is an arithmetic number, because the mean of its divisors is an integer number (153180720).

Almost surely, 2^21138569760 is an apocalyptic number.

21138569760 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 21138569760, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (44116047360).

21138569760 is an abundant number, since it is smaller than the sum of its proper divisors (67093524960).

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

21138569760 is a wasteful number, since it uses less digits than its factorization.

21138569760 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2049 (or 2024 counting only the distinct ones).

The product of its (nonzero) digits is 544320, while the sum is 48.

The spelling of 21138569760 in words is "twenty-one billion, one hundred thirty-eight million, five hundred sixty-nine thousand, seven hundred sixty".