221221234212 has 96 divisors (see below), whose sum is σ = 579027778560. Its totient is φ = 65145985920.

The previous prime is 221221234177. The next prime is 221221234229. The reversal of 221221234212 is 212432122122.

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

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 4070683 + ... + 4124669.

It is an arithmetic number, because the mean of its divisors is an integer number (6031539360).

Almost surely, 2^221221234212 is an apocalyptic number.

221221234212 is a gapful number since it is divisible by the number (22) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 221221234212, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (289513889280).

221221234212 is an abundant number, since it is smaller than the sum of its proper divisors (357806544348).

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

221221234212 is a wasteful number, since it uses less digits than its factorization.

221221234212 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 54881 (or 54879 counting only the distinct ones).

The product of its digits is 1536, while the sum is 24.

Adding to 221221234212 its reverse (212432122122), we get a palindrome (433653356334).

The spelling of 221221234212 in words is "two hundred twenty-one billion, two hundred twenty-one million, two hundred thirty-four thousand, two hundred twelve".