21253226121216 has 192 divisors, whose sum is σ = 63227388369600. Its totient is φ = 7053999243264.

The previous prime is 21253226121209. The next prime is 21253226121217. The reversal of 21253226121216 is 61212162235212.

21253226121216 is a `hidden beast` number, since 2 + 1 + 2 + 5 + 3 + 22 + 612 + 1 + 2 + 16 = 666.

It is a tau number, because it is divible by the number of its divisors (192).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is not an unprimeable number, because it can be changed into a prime (21253226121217) by changing a digit.

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 15 ways as a sum of consecutive naturals, for example, 12059175 + ... + 13708761.

It is an arithmetic number, because the mean of its divisors is an integer number (329309314425).

Almost surely, 2^{21253226121216} 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 21253226121216, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (31613694184800).

21253226121216 is an abundant number, since it is smaller than the sum of its proper divisors (41974162248384).

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

21253226121216 is a wasteful number, since it uses less digits than its factorization.

21253226121216 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1649851 (or 1649825 counting only the distinct ones).

The product of its digits is 34560, while the sum is 36.

Adding to 21253226121216 its reverse (61212162235212), we get a palindrome (82465388356428).

The spelling of 21253226121216 in words is "twenty-one trillion, two hundred fifty-three billion, two hundred twenty-six million, one hundred twenty-one thousand, two hundred sixteen".