21371801856768 has 1728 divisors, whose sum is σ = 76977953095680. Its totient is φ = 5618427494400.

The previous prime is 21371801856767. The next prime is 21371801856791. The reversal of 21371801856768 is 86765810817312.

21371801856768 is a `hidden beast` number, since 2 + 1 + 3 + 7 + 1 + 8 + 0 + 1 + 8 + 567 + 68 = 666.

It is not an unprimeable number, because it can be changed into a prime (21371801856767) by changing a digit.

It is a polite number, since it can be written in 191 ways as a sum of consecutive naturals, for example, 63417809496 + ... + 63417809832.

It is an arithmetic number, because the mean of its divisors is an integer number (44547426560).

Almost surely, 2^{21371801856768} is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21371801856768, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (38488976547840).

21371801856768 is an abundant number, since it is smaller than the sum of its proper divisors (55606151238912).

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

21371801856768 is a wasteful number, since it uses less digits than its factorization.

21371801856768 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 594 (or 577 counting only the distinct ones).

The product of its (nonzero) digits is 27095040, while the sum is 63.

The spelling of 21371801856768 in words is "twenty-one trillion, three hundred seventy-one billion, eight hundred one million, eight hundred fifty-six thousand, seven hundred sixty-eight".