21021201100100 has 72 divisors (see below), whose sum is σ = 46440962312136. Its totient is φ = 8256873600000.

The previous prime is 21021201100051. The next prime is 21021201100127. The reversal of 21021201100100 is 100110212012.

It can be written as a sum of positive squares in 12 ways, for example, as 12023264981764 + 8997936118336 = 3467458^2 + 2999656^2 .

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 799130 + ... + 6533070.

Almost surely, 2^{21021201100100} is an apocalyptic number.

21021201100100 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 21021201100100, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (23220481156068).

21021201100100 is an abundant number, since it is smaller than the sum of its proper divisors (25419761212036).

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

21021201100100 is a wasteful number, since it uses less digits than its factorization.

21021201100100 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5734617 (or 5734610 counting only the distinct ones).

The product of its (nonzero) digits is 8, while the sum is 11.

Adding to 21021201100100 its reverse (100110212012), we get a palindrome (21121311312112).

The spelling of 21021201100100 in words is "twenty-one trillion, twenty-one billion, two hundred one million, one hundred thousand, one hundred".