221021121121020 has 288 divisors, whose sum is σ = 732863770329600. Its totient is φ = 53472213434880.

The previous prime is 221021121121007. The next prime is 221021121121127. The reversal of 221021121121020 is 20121121120122.

221021121121020 is a `hidden beast` number, since 2 + 2 + 10 + 211 + 211 + 210 + 20 = 666.

221021121121020 is digitally balanced in base 2 and base 4, because in such bases it contains all the possibile digits an equal number of times.

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a junction number, because it is equal to n+sod(n) for n = 221021121120984 and 221021121121002.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 1940444031 + ... + 1940557929.

It is an arithmetic number, because the mean of its divisors is an integer number (2544665869200).

Almost surely, 2^{221021121121020} is an apocalyptic number.

221021121121020 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 221021121121020, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (366431885164800).

221021121121020 is an abundant number, since it is smaller than the sum of its proper divisors (511842649208580).

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

221021121121020 is a wasteful number, since it uses less digits than its factorization.

221021121121020 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 115905 (or 115900 counting only the distinct ones).

The product of its (nonzero) digits is 64, while the sum is 18.

Adding to 221021121121020 its reverse (20121121120122), we get a palindrome (241142242241142).

The spelling of 221021121121020 in words is "two hundred twenty-one trillion, twenty-one billion, one hundred twenty-one million, one hundred twenty-one thousand, twenty".