21380507568 has 240 divisors, whose sum is σ = 72128359680. Its totient is φ = 5775515136.

The previous prime is 21380507527. The next prime is 21380507633. The reversal of 21380507568 is 86570508312.

21380507568 is a `hidden beast` number, since 2 + 1 + 3 + 80 + 5 + 0 + 7 + 568 = 666.

It is a super-2 number, since 2×21380507568² (a number of 21 digits) contains 22 as substring.

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 47 ways as a sum of consecutive naturals, for example, 14037655 + ... + 14039177.

It is an arithmetic number, because the mean of its divisors is an integer number (300534832).

Almost surely, 2^21380507568 is an apocalyptic number.

21380507568 is a gapful number since it is divisible by the number (28) 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 21380507568, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (36064179840).

21380507568 is an abundant number, since it is smaller than the sum of its proper divisors (50747852112).

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

21380507568 is a wasteful number, since it uses less digits than its factorization.

21380507568 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2296 (or 2287 counting only the distinct ones).

The product of its (nonzero) digits is 403200, while the sum is 45.

The spelling of 21380507568 in words is "twenty-one billion, three hundred eighty million, five hundred seven thousand, five hundred sixty-eight".