21173972719680 has 1344 divisors, whose sum is σ = 88364436814080. Its totient is φ = 4751695872000.

The previous prime is 21173972719651. The next prime is 21173972719681. The reversal of 21173972719680 is 8691727937112.

21173972719680 is a `hidden beast` number, since 2 + 1 + 17 + 397 + 2 + 71 + 96 + 80 = 666.

It is not an unprimeable number, because it can be changed into a prime (21173972719681) 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, 1084111515 + ... + 1084131045.

It is an arithmetic number, because the mean of its divisors is an integer number (65747348820).

Almost surely, 2^{21173972719680} is an apocalyptic number.

21173972719680 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 21173972719680, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (44182218407040).

21173972719680 is an abundant number, since it is smaller than the sum of its proper divisors (67190464094400).

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

21173972719680 is a wasteful number, since it uses less digits than its factorization.

21173972719680 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 19657 (or 19630 counting only the distinct ones).

The product of its (nonzero) digits is 16003008, while the sum is 63.

The spelling of 21173972719680 in words is "twenty-one trillion, one hundred seventy-three billion, nine hundred seventy-two million, seven hundred nineteen thousand, six hundred eighty".