21221122220100 has 216 divisors, whose sum is σ = 72593984500128. Its totient is φ = 5142344486400.

The previous prime is 21221122220093. The next prime is 21221122220117. The reversal of 21221122220100 is 102222112212.

It is a happy number.

21221122220100 is a `hidden beast` number, since 2 + 1 + 221 + 122 + 220 + 100 = 666.

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

It is an unprimeable number.

It is a polite number, since it can be written in 71 ways as a sum of consecutive naturals, for example, 23081407 + ... + 23983193.

Almost surely, 2^{21221122220100} is an apocalyptic number.

21221122220100 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 21221122220100, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (36296992250064).

21221122220100 is an abundant number, since it is smaller than the sum of its proper divisors (51372862280028).

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

21221122220100 is a wasteful number, since it uses less digits than its factorization.

21221122220100 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 904195 (or 904185 counting only the distinct ones).

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

Adding to 21221122220100 its reverse (102222112212), we get a palindrome (21323344332312).

The spelling of 21221122220100 in words is "twenty-one trillion, two hundred twenty-one billion, one hundred twenty-two million, two hundred twenty thousand, one hundred".