21612644353072 has 80 divisors (see below), whose sum is σ = 44896346396352. Its totient is φ = 10052575441920.

The previous prime is 21612644353061. The next prime is 21612644353123. The reversal of 21612644353072 is 27035344621612.

It is a Harshad number since it is a multiple of its sum of digits (46).

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 29883798 + ... + 30598474.

Almost surely, 2^{21612644353072} 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 21612644353072, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (22448173198176).

21612644353072 is an abundant number, since it is smaller than the sum of its proper divisors (23283702043280).

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

21612644353072 is a wasteful number, since it uses less digits than its factorization.

21612644353072 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 716966 (or 716960 counting only the distinct ones).

The product of its (nonzero) digits is 1451520, while the sum is 46.

Adding to 21612644353072 its reverse (27035344621612), we get a palindrome (48647988974684).

The spelling of 21612644353072 in words is "twenty-one trillion, six hundred twelve billion, six hundred forty-four million, three hundred fifty-three thousand, seventy-two".