221021122120020 has 36 divisors (see below), whose sum is σ = 670430737097940. Its totient is φ = 58938965898624.

The previous prime is 221021122119953. The next prime is 221021122120021. The reversal of 221021122120020 is 20021221120122.

It is a happy number.

221021122120020 is a `hidden beast` number, since 2 + 2 + 10 + 211 + 221 + 200 + 20 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 174823082196624 + 46198039923396 = 13222068^2 + 6796914^2 .

It is a tau number, because it is divible by the number of its divisors (36).

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 = 221021122119975 and 221021122120002.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (221021122120021) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 613947561265 + ... + 613947561624.

Almost surely, 2^{221021122120020} is an apocalyptic number.

221021122120020 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

221021122120020 is an abundant number, since it is smaller than the sum of its proper divisors (449409614977920).

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

221021122120020 is a wasteful number, since it uses less digits than its factorization.

221021122120020 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1227895122904 (or 1227895122899 counting only the distinct ones).

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

Adding to 221021122120020 its reverse (20021221120122), we get a palindrome (241042343240142).

The spelling of 221021122120020 in words is "two hundred twenty-one trillion, twenty-one billion, one hundred twenty-two million, one hundred twenty thousand, twenty".