21221451420500 has 96 divisors (see below), whose sum is σ = 46876172249088. Its totient is φ = 8392327056000.

The previous prime is 21221451420461. The next prime is 21221451420529. The reversal of 21221451420500 is 502415412212.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 14884862 + ... + 16248138.

It is an arithmetic number, because the mean of its divisors is an integer number (488293460928).

Almost surely, 2^{21221451420500} is an apocalyptic number.

21221451420500 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 21221451420500, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (23438086124544).

21221451420500 is an abundant number, since it is smaller than the sum of its proper divisors (25654720828588).

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

21221451420500 is a wasteful number, since it uses less digits than its factorization.

21221451420500 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1363650 (or 1363638 counting only the distinct ones).

The product of its (nonzero) digits is 6400, while the sum is 29.

Adding to 21221451420500 its reverse (502415412212), we get a palindrome (21723866832712).

The spelling of 21221451420500 in words is "twenty-one trillion, two hundred twenty-one billion, four hundred fifty-one million, four hundred twenty thousand, five hundred".