221021000100 has 432 divisors, whose sum is σ = 784142311680. Its totient is φ = 51762585600.

The previous prime is 221021000089. The next prime is 221021000107. The reversal of 221021000100 is 1000120122.

221021000100 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a Harshad number since it is a multiple of its sum of digits (9).

It is not an unprimeable number, because it can be changed into a prime (221021000107) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 143 ways as a sum of consecutive naturals, for example, 14420241 + ... + 14435559.

It is an arithmetic number, because the mean of its divisors is an integer number (1815144240).

Almost surely, 2^221021000100 is an apocalyptic number.

221021000100 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 221021000100, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (392071155840).

221021000100 is an abundant number, since it is smaller than the sum of its proper divisors (563121311580).

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

221021000100 is a wasteful number, since it uses less digits than its factorization.

221021000100 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 15420 (or 15410 counting only the distinct ones).

The product of its (nonzero) digits is 8, while the sum is 9.

Adding to 221021000100 its reverse (1000120122), we get a palindrome (222021120222).

The spelling of 221021000100 in words is "two hundred twenty-one billion, twenty-one million, one hundred", and thus it is an aban number.