21661360091136 has 624 divisors, whose sum is σ = 71273211959040. Its totient is φ = 6542888140800.

The previous prime is 21661360091083. The next prime is 21661360091177. The reversal of 21661360091136 is 63119006316612.

21661360091136 is a `hidden beast` number, since 2 + 1 + 6 + 6 + 1 + 3 + 600 + 9 + 1 + 1 + 36 = 666.

It is a junction number, because it is equal to n+sod(n) for n = 21661360091091 and 21661360091100.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 434933436 + ... + 434983236.

It is an arithmetic number, because the mean of its divisors is an integer number (114219890960).

Almost surely, 2^{21661360091136} is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21661360091136, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (35636605979520).

21661360091136 is an abundant number, since it is smaller than the sum of its proper divisors (49611851867904).

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

21661360091136 is an equidigital number, since it uses as much as digits as its factorization.

21661360091136 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 49882 (or 49848 counting only the distinct ones).

The product of its (nonzero) digits is 209952, while the sum is 45.

The spelling of 21661360091136 in words is "twenty-one trillion, six hundred sixty-one billion, three hundred sixty million, ninety-one thousand, one hundred thirty-six".