21213543326624 has 96 divisors (see below), whose sum is σ = 45959024704320. Its totient is φ = 9558474393600.

The previous prime is 21213543326581. The next prime is 21213543326639. The reversal of 21213543326624 is 42662334531212.

It is a Harshad number since it is a multiple of its sum of digits (44).

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, 31618004 + ... + 32281964.

It is an arithmetic number, because the mean of its divisors is an integer number (478739840670).

Almost surely, 2^{21213543326624} 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 21213543326624, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (22979512352160).

21213543326624 is an abundant number, since it is smaller than the sum of its proper divisors (24745481377696).

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

21213543326624 is a wasteful number, since it uses less digits than its factorization.

21213543326624 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 664774 (or 664766 counting only the distinct ones).

The product of its digits is 1244160, while the sum is 44.

Adding to 21213543326624 its reverse (42662334531212), we get a palindrome (63875877857836).

The spelling of 21213543326624 in words is "twenty-one trillion, two hundred thirteen billion, five hundred forty-three million, three hundred twenty-six thousand, six hundred twenty-four".