221420100 has 144 divisors (see below), whose sum is σ = 704329920. Its totient is φ = 53260800.

The previous prime is 221420077. The next prime is 221420107. The reversal of 221420100 is 1024122.

It is a Harshad number since it is a multiple of its sum of digits (12).

It is not an unprimeable number, because it can be changed into a prime (221420107) 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, 755554 + ... + 755846.

It is an arithmetic number, because the mean of its divisors is an integer number (4891180).

Almost surely, 2^221420100 is an apocalyptic number.

221420100 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 221420100, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (352164960).

221420100 is an abundant number, since it is smaller than the sum of its proper divisors (482909820).

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

221420100 is a wasteful number, since it uses less digits than its factorization.

221420100 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 550 (or 543 counting only the distinct ones).

The product of its (nonzero) digits is 32, while the sum is 12.

The square root of 221420100 is about 14880.1915310254. The cubic root of 221420100 is about 604.9772092592.

Adding to 221420100 its reverse (1024122), we get a palindrome (222444222).

The spelling of 221420100 in words is "two hundred twenty-one million, four hundred twenty thousand, one hundred".