21222221211212 has 12 divisors (see below), whose sum is σ = 42444442422480. Its totient is φ = 9095237661936.

The previous prime is 21222221211211. The next prime is 21222221211221. The reversal of 21222221211212 is 21211212222212.

21222221211212 is an admirable number.

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 (21222221211211) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 378968235887 + ... + 378968235942.

It is an arithmetic number, because the mean of its divisors is an integer number (3537036868540).

Almost surely, 2^{21222221211212} is an apocalyptic number.

It is an amenable number.

21222221211212 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

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

21222221211212 is a wasteful number, since it uses less digits than its factorization.

21222221211212 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 757936471840 (or 757936471838 counting only the distinct ones).

The product of its digits is 512, while the sum is 23.

Adding to 21222221211212 its reverse (21211212222212), we get a palindrome (42433433433424).

The spelling of 21222221211212 in words is "twenty-one trillion, two hundred twenty-two billion, two hundred twenty-one million, two hundred eleven thousand, two hundred twelve".