21221352520320 has 512 divisors, whose sum is σ = 70545758976000. Its totient is φ = 5420199444480.

The previous prime is 21221352520259. The next prime is 21221352520367. The reversal of 21221352520320 is 2302525312212.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (30).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 2845826032 + ... + 2845833488.

It is an arithmetic number, because the mean of its divisors is an integer number (137784685500).

Almost surely, 2^{21221352520320} is an apocalyptic number.

21221352520320 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 21221352520320, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (35272879488000).

21221352520320 is an abundant number, since it is smaller than the sum of its proper divisors (49324406455680).

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

21221352520320 is a wasteful number, since it uses less digits than its factorization.

21221352520320 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7996 (or 7984 counting only the distinct ones).

The product of its (nonzero) digits is 14400, while the sum is 30.

Adding to 21221352520320 its reverse (2302525312212), we get a palindrome (23523877832532).

The spelling of 21221352520320 in words is "twenty-one trillion, two hundred twenty-one billion, three hundred fifty-two million, five hundred twenty thousand, three hundred twenty".