21006808872000 has 896 divisors, whose sum is σ = 82585190338560. Its totient is φ = 4604958720000.

The previous prime is 21006808871989. The next prime is 21006808872013. The reversal of 21006808872000 is 27880860012.

It is a Harshad number since it is a multiple of its sum of digits (42).

It is an unprimeable number.

It is a polite number, since it can be written in 127 ways as a sum of consecutive naturals, for example, 406366155 + ... + 406417845.

It is an arithmetic number, because the mean of its divisors is an integer number (92170971360).

Almost surely, 2^{21006808872000} is an apocalyptic number.

21006808872000 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 21006808872000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (41292595169280).

21006808872000 is an abundant number, since it is smaller than the sum of its proper divisors (61578381466560).

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

21006808872000 is a wasteful number, since it uses less digits than its factorization.

21006808872000 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 51828 (or 51808 counting only the distinct ones).

The product of its (nonzero) digits is 86016, while the sum is 42.

The spelling of 21006808872000 in words is "twenty-one trillion, six billion, eight hundred eight million, eight hundred seventy-two thousand".