21138485760 has 400 divisors, whose sum is σ = 86533229376. Its totient is φ = 4831322112.

The previous prime is 21138485741. The next prime is 21138485773. The reversal of 21138485760 is 6758483112.

21138485760 is a `hidden beast` number, since 2 + 1 + 1 + 38 + 48 + 576 + 0 = 666.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 1444239 + ... + 1458801.

Almost surely, 2^21138485760 is an apocalyptic number.

21138485760 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 21138485760, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (43266614688).

21138485760 is an abundant number, since it is smaller than the sum of its proper divisors (65394743616).

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

21138485760 is an equidigital number, since it uses as much as digits as its factorization.

21138485760 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 14605 (or 14580 counting only the distinct ones).

The product of its (nonzero) digits is 322560, while the sum is 45.

The spelling of 21138485760 in words is "twenty-one billion, one hundred thirty-eight million, four hundred eighty-five thousand, seven hundred sixty".