221431212 has 96 divisors (see below), whose sum is σ = 605875200. Its totient is φ = 69797376.

The previous prime is 221431169. The next prime is 221431213. The reversal of 221431212 is 212134122.

It is a happy number.

221431212 is a `hidden beast` number, since 2 + 21 + 431 + 212 = 666.

221431212 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 (18).

It is a nude number because it is divisible by every one of its digits.

It is not an unprimeable number, because it can be changed into a prime (221431213) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 240489 + ... + 241407.

It is an arithmetic number, because the mean of its divisors is an integer number (6311200).

Almost surely, 2^221431212 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 221431212, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (302937600).

221431212 is an abundant number, since it is smaller than the sum of its proper divisors (384443988).

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

221431212 is a wasteful number, since it uses less digits than its factorization.

221431212 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1052 (or 1044 counting only the distinct ones).

The product of its digits is 192, while the sum is 18.

The square root of 221431212 is about 14880.5649086317. The cubic root of 221431212 is about 604.9873293797.

Adding to 221431212 its reverse (212134122), we get a palindrome (433565334).

The spelling of 221431212 in words is "two hundred twenty-one million, four hundred thirty-one thousand, two hundred twelve".