221221203100 has 144 divisors (see below), whose sum is σ = 505889558496. Its totient is φ = 83884032000.

The previous prime is 221221203061. The next prime is 221221203101. The reversal of 221221203100 is 1302122122.

It is a happy number.

It is a super-2 number, since 2×221221203100² (a number of 23 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (221221203101) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 20752972 + ... + 20763628.

It is an arithmetic number, because the mean of its divisors is an integer number (3513121934).

Almost surely, 2^221221203100 is an apocalyptic number.

221221203100 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 221221203100, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (252944779248).

221221203100 is an abundant number, since it is smaller than the sum of its proper divisors (284668355396).

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

221221203100 is a wasteful number, since it uses less digits than its factorization.

221221203100 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10856 (or 10849 counting only the distinct ones).

The product of its (nonzero) digits is 96, while the sum is 16.

Adding to 221221203100 its reverse (1302122122), we get a palindrome (222523325222).

The spelling of 221221203100 in words is "two hundred twenty-one billion, two hundred twenty-one million, two hundred three thousand, one hundred".