21243155421224 has 144 divisors (see below), whose sum is σ = 45258250161600. Its totient is φ = 9340508865600.

The previous prime is 21243155421181. The next prime is 21243155421259. The reversal of 21243155421224 is 42212455134212.

It is a happy number.

It is an unprimeable number.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 3645638999 + ... + 3645644825.

It is an arithmetic number, because the mean of its divisors is an integer number (314293403900).

Almost surely, 2^{21243155421224} 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 21243155421224, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (22629125080800).

21243155421224 is an abundant number, since it is smaller than the sum of its proper divisors (24015094740376).

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

21243155421224 is a wasteful number, since it uses less digits than its factorization.

21243155421224 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9836 (or 9790 counting only the distinct ones).

The product of its digits is 153600, while the sum is 38.

It can be divided in two parts, 212431 and 55421224, that added together give a palindrome (55633655).

The spelling of 21243155421224 in words is "twenty-one trillion, two hundred forty-three billion, one hundred fifty-five million, four hundred twenty-one thousand, two hundred twenty-four".