221211100 has 36 divisors (see below), whose sum is σ = 523669608. Its totient is φ = 80440000.

The previous prime is 221211083. The next prime is 221211127. The reversal of 221211100 is 1112122.

It is a Harshad number since it is a multiple of its sum of digits (10).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 99451 + ... + 101650.

It is an arithmetic number, because the mean of its divisors is an integer number (14546378).

Almost surely, 2^221211100 is an apocalyptic number.

221211100 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

221211100 is an abundant number, since it is smaller than the sum of its proper divisors (302458508).

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

221211100 is a wasteful number, since it uses less digits than its factorization.

221211100 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 201126 (or 201119 counting only the distinct ones).

The product of its (nonzero) digits is 8, while the sum is 10.

The square root of 221211100 is about 14873.1671139674. The cubic root of 221211100 is about 604.7868019140.

Adding to 221211100 its reverse (1112122), we get a palindrome (222323222).

The spelling of 221211100 in words is "two hundred twenty-one million, two hundred eleven thousand, one hundred".