221101212 has 24 divisors (see below), whose sum is σ = 517917456. Its totient is φ = 73412608.

The previous prime is 221101211. The next prime is 221101217. The reversal of 221101212 is 212101122.

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (221101211) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 32763 + ... + 38930.

It is an arithmetic number, because the mean of its divisors is an integer number (21579894).

Almost surely, 2^221101212 is an apocalyptic number.

It is an amenable number.

221101212 is an abundant number, since it is smaller than the sum of its proper divisors (296816244).

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

221101212 is a wasteful number, since it uses less digits than its factorization.

221101212 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 71957 (or 71955 counting only the distinct ones).

The product of its (nonzero) digits is 16, while the sum is 12.

The square root of 221101212 is about 14869.4724855995. The cubic root of 221101212 is about 604.6866414493.

Adding to 221101212 its reverse (212101122), we get a palindrome (433202334).

The spelling of 221101212 in words is "two hundred twenty-one million, one hundred one thousand, two hundred twelve".