221212312 has 8 divisors (see below), whose sum is σ = 414773100. Its totient is φ = 110606152.

The previous prime is 221212309. The next prime is 221212333. The reversal of 221212312 is 213212122.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (8).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 13825762 + ... + 13825777.

Almost surely, 2^221212312 is an apocalyptic number.

It is an amenable number.

221212312 is a deficient number, since it is larger than the sum of its proper divisors (193560788).

221212312 is a wasteful number, since it uses less digits than its factorization.

221212312 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 27651545 (or 27651541 counting only the distinct ones).

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

The square root of 221212312 is about 14873.2078584279. The cubic root of 221212312 is about 604.7879064401.

Adding to 221212312 its reverse (213212122), we get a palindrome (434424434).

The spelling of 221212312 in words is "two hundred twenty-one million, two hundred twelve thousand, three hundred twelve".