221121211212 has 72 divisors (see below), whose sum is σ = 609814073232. Its totient is φ = 67000320000.

The previous prime is 221121211183. The next prime is 221121211219. The reversal of 221121211212 is 212112121122.

221121211212 is a `hidden beast` number, since 221 + 1 + 21 + 211 + 212 = 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 not an unprimeable number, because it can be changed into a prime (221121211219) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 6318948 + ... + 6353844.

It is an arithmetic number, because the mean of its divisors is an integer number (8469639906).

Almost surely, 2^221121211212 is an apocalyptic number.

221121211212 is a gapful number since it is divisible by the number (22) formed by its first and last digit.

It is an amenable number.

221121211212 is an abundant number, since it is smaller than the sum of its proper divisors (388692862020).

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

221121211212 is a wasteful number, since it uses less digits than its factorization.

221121211212 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 50919 (or 50914 counting only the distinct ones).

The product of its digits is 64, while the sum is 18.

Adding to 221121211212 its reverse (212112121122), we get a palindrome (433233332334).

The spelling of 221121211212 in words is "two hundred twenty-one billion, one hundred twenty-one million, two hundred eleven thousand, two hundred twelve".