221201210221020 has 144 divisors (see below), whose sum is σ = 679101019283232. Its totient is φ = 58272873914880.

The previous prime is 221201210221009. The next prime is 221201210221037. The reversal of 221201210221020 is 20122012102122.

It is a happy number.

221201210221020 is a `hidden beast` number, since 2 + 21 + 201 + 210 + 2 + 210 + 20 = 666.

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 = 221201210220984 and 221201210221002.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 258647634 + ... + 259501446.

It is an arithmetic number, because the mean of its divisors is an integer number (4715979300578).

Almost surely, 2^{221201210221020} is an apocalyptic number.

221201210221020 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 221201210221020, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (339550509641616).

221201210221020 is an abundant number, since it is smaller than the sum of its proper divisors (457899809062212).

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

221201210221020 is a wasteful number, since it uses less digits than its factorization.

221201210221020 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 871252 (or 871247 counting only the distinct ones).

The product of its (nonzero) digits is 128, while the sum is 18.

Adding to 221201210221020 its reverse (20122012102122), we get a palindrome (241323222323142).

The spelling of 221201210221020 in words is "two hundred twenty-one trillion, two hundred one billion, two hundred ten million, two hundred twenty-one thousand, twenty".