221401212 has 12 divisors (see below), whose sum is σ = 516602856. Its totient is φ = 73800400.

The previous prime is 221401199. The next prime is 221401261. The reversal of 221401212 is 212104122.

It is a tau number, because it is divible by the number of its divisors (12).

It is a junction number, because it is equal to n+sod(n) for n = 221401191 and 221401200.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 9225039 + ... + 9225062.

It is an arithmetic number, because the mean of its divisors is an integer number (43050238).

Almost surely, 2^221401212 is an apocalyptic number.

It is an amenable number.

221401212 is an abundant number, since it is smaller than the sum of its proper divisors (295201644).

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

221401212 is a wasteful number, since it uses less digits than its factorization.

221401212 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 18450108 (or 18450106 counting only the distinct ones).

The product of its (nonzero) digits is 64, while the sum is 15.

The square root of 221401212 is about 14879.5568482398. The cubic root of 221401212 is about 604.9600064631.

Adding to 221401212 its reverse (212104122), we get a palindrome (433505334).

The spelling of 221401212 in words is "two hundred twenty-one million, four hundred one thousand, two hundred twelve".