221312412 has 60 divisors (see below), whose sum is σ = 584369016. Its totient is φ = 73029600.

The previous prime is 221312411. The next prime is 221312419. The reversal of 221312412 is 214213122.

It is a happy number.

221312412 is a `hidden beast` number, since 221 + 31 + 2 + 412 = 666.

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 a congruent number.

It is not an unprimeable number, because it can be changed into a prime (221312411) by changing a digit.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 29343 + ... + 36105.

Almost surely, 2^221312412 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 221312412, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (292184508).

221312412 is an abundant number, since it is smaller than the sum of its proper divisors (363056604).

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

221312412 is a wasteful number, since it uses less digits than its factorization.

221312412 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6880 (or 6869 counting only the distinct ones).

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

The square root of 221312412 is about 14876.5725891416. The cubic root of 221312412 is about 604.8791161618.

Adding to 221312412 its reverse (214213122), we get a palindrome (435525534).

The spelling of 221312412 in words is "two hundred twenty-one million, three hundred twelve thousand, four hundred twelve".