21186357916680 has 640 divisors, whose sum is σ = 82932982133760. Its totient is φ = 4833947289600.

The previous prime is 21186357916679. The next prime is 21186357916727. The reversal of 21186357916680 is 8661975368112.

21186357916680 is a `hidden beast` number, since 2 + 118 + 6 + 357 + 9 + 166 + 8 + 0 = 666.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 159 ways as a sum of consecutive naturals, for example, 73166985 + ... + 73455975.

It is an arithmetic number, because the mean of its divisors is an integer number (129582784584).

Almost surely, 2^{21186357916680} is an apocalyptic number.

21186357916680 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 21186357916680, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (41466491066880).

21186357916680 is an abundant number, since it is smaller than the sum of its proper divisors (61746624217080).

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

21186357916680 is a wasteful number, since it uses less digits than its factorization.

21186357916680 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 289064 (or 289029 counting only the distinct ones).

The product of its (nonzero) digits is 26127360, while the sum is 63.

The spelling of 21186357916680 in words is "twenty-one trillion, one hundred eighty-six billion, three hundred fifty-seven million, nine hundred sixteen thousand, six hundred eighty".