21121311206160 has 720 divisors, whose sum is σ = 78938656196400. Its totient is φ = 5056651100160.

The previous prime is 21121311206153. The next prime is 21121311206173. The reversal of 21121311206160 is 6160211312112.

21121311206160 is a `hidden beast` number, since 2 + 1 + 1 + 2 + 1 + 31 + 12 + 0 + 616 + 0 = 666.

It can be written as a sum of positive squares in 8 ways, for example, as 9234441216 + 21112076764944 = 96096^2 + 4594788^2 .

It is a tau number, because it is divible by the number of its divisors (720).

It is a super-2 number, since 2×21121311206160² (a number of 27 digits) contains 22 as substring.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 143 ways as a sum of consecutive naturals, for example, 12475670274 + ... + 12475671966.

It is an arithmetic number, because the mean of its divisors is an integer number (109637022495).

Almost surely, 2^{21121311206160} is an apocalyptic number.

21121311206160 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 21121311206160, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (39469328098200).

21121311206160 is an abundant number, since it is smaller than the sum of its proper divisors (57817344990240).

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

21121311206160 is a wasteful number, since it uses less digits than its factorization.

21121311206160 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3432 (or 3412 counting only the distinct ones).

The product of its (nonzero) digits is 864, while the sum is 27.

Adding to 21121311206160 its reverse (6160211312112), we get a palindrome (27281522518272).

The spelling of 21121311206160 in words is "twenty-one trillion, one hundred twenty-one billion, three hundred eleven million, two hundred six thousand, one hundred sixty".