21215650916736 has 320 divisors, whose sum is σ = 67145675982000. Its totient is φ = 6630604406784.

The previous prime is 21215650916723. The next prime is 21215650916773. The reversal of 21215650916736 is 63761905651212.

21215650916736 is a `hidden beast` number, since 2 + 1 + 2 + 1 + 56 + 509 + 16 + 73 + 6 = 666.

It is a Harshad number since it is a multiple of its sum of digits (54).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 18553080 + ... + 19663368.

Almost surely, 2^{21215650916736} 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 21215650916736, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (33572837991000).

21215650916736 is an abundant number, since it is smaller than the sum of its proper divisors (45930025065264).

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

21215650916736 is a wasteful number, since it uses less digits than its factorization.

21215650916736 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1110431 (or 1110410 counting only the distinct ones).

The product of its (nonzero) digits is 4082400, while the sum is 54.

The spelling of 21215650916736 in words is "twenty-one trillion, two hundred fifteen billion, six hundred fifty million, nine hundred sixteen thousand, seven hundred thirty-six".