21221021231320 has 256 divisors, whose sum is σ = 51886629043200. Its totient is φ = 7783776000000.

The previous prime is 21221021231317. The next prime is 21221021231341. The reversal of 21221021231320 is 2313212012212.

It is a junction number, because it is equal to n+sod(n) for n = 21221021231291 and 21221021231300.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 9182612965 + ... + 9182615275.

It is an arithmetic number, because the mean of its divisors is an integer number (202682144700).

Almost surely, 2^{21221021231320} is an apocalyptic number.

21221021231320 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21221021231320, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (25943314521600).

21221021231320 is an abundant number, since it is smaller than the sum of its proper divisors (30665607811880).

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

21221021231320 is a wasteful number, since it uses less digits than its factorization.

21221021231320 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3930 (or 3926 counting only the distinct ones).

The product of its (nonzero) digits is 576, while the sum is 22.

Adding to 21221021231320 its reverse (2313212012212), we get a palindrome (23534233243532).

The spelling of 21221021231320 in words is "twenty-one trillion, two hundred twenty-one billion, twenty-one million, two hundred thirty-one thousand, three hundred twenty".