221221200000020 has 96 divisors (see below), whose sum is σ = 524356924654080. Its totient is φ = 77657771018240.

The previous prime is 221221199999881. The next prime is 221221200000071. The reversal of 221221200000020 is 20000002122122.

It is a junction number, because it is equal to n+sod(n) for n = 221221199999950 and 221221200000004.

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, 37353452 + ... + 42868668.

It is an arithmetic number, because the mean of its divisors is an integer number (5462051298480).

Almost surely, 2^{221221200000020} is an apocalyptic number.

221221200000020 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 221221200000020, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (262178462327040).

221221200000020 is an abundant number, since it is smaller than the sum of its proper divisors (303135724654060).

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

221221200000020 is a wasteful number, since it uses less digits than its factorization.

221221200000020 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5521553 (or 5521551 counting only the distinct ones).

The product of its (nonzero) digits is 64, while the sum is 14.

Adding to 221221200000020 its reverse (20000002122122), we get a palindrome (241221202122142).

The spelling of 221221200000020 in words is "two hundred twenty-one trillion, two hundred twenty-one billion, two hundred million, twenty", and thus it is an aban number.