21399866688000 has 640 divisors, whose sum is σ = 73594958621184. Its totient is φ = 5513183232000.

The previous prime is 21399866687921. The next prime is 21399866688071. The reversal of 21399866688000 is 88666899312.

It is a tau number, because it is divible by the number of its divisors (640).

It is an unprimeable number.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 810802804 + ... + 810829196.

Almost surely, 2^{21399866688000} is an apocalyptic number.

21399866688000 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 21399866688000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (36797479310592).

21399866688000 is an abundant number, since it is smaller than the sum of its proper divisors (52195091933184).

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

21399866688000 is a wasteful number, since it uses less digits than its factorization.

21399866688000 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 26573 (or 26547 counting only the distinct ones).

The product of its (nonzero) digits is 53747712, while the sum is 66.

The spelling of 21399866688000 in words is "twenty-one trillion, three hundred ninety-nine billion, eight hundred sixty-six million, six hundred eighty-eight thousand".