21102221221020 has 144 divisors (see below), whose sum is σ = 64585425576672. Its totient is φ = 5576692101120.

The previous prime is 21102221221013. The next prime is 21102221221069. The reversal of 21102221221020 is 2012212220112.

It is a happy number.

21102221221020 is a `hidden beast` number, since 211 + 0 + 2 + 221 + 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 = 21102221220984 and 21102221221002.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 156001215 + ... + 156136425.

It is an arithmetic number, because the mean of its divisors is an integer number (448509899838).

Almost surely, 2^{21102221221020} is an apocalyptic number.

21102221221020 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 21102221221020, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (32292712788336).

21102221221020 is an abundant number, since it is smaller than the sum of its proper divisors (43483204355652).

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

21102221221020 is a wasteful number, since it uses less digits than its factorization.

21102221221020 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 143012 (or 143007 counting only the distinct ones).

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

Adding to 21102221221020 its reverse (2012212220112), we get a palindrome (23114433441132).

It can be divided in two parts, 21102 and 221221020, that added together give a palindrome (221242122).

The spelling of 21102221221020 in words is "twenty-one trillion, one hundred two billion, two hundred twenty-one million, two hundred twenty-one thousand, twenty".