21222312212 has 6 divisors (see below), whose sum is σ = 37139046378. Its totient is φ = 10611156104.

The previous prime is 21222312197. The next prime is 21222312217. The reversal of 21222312212 is 21221322212.

It can be written as a sum of positive squares in only one way, i.e., 18899650576 + 2322661636 = 137476^2 + 48194^2 .

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21222312217) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2652789023 + ... + 2652789030.

It is an arithmetic number, because the mean of its divisors is an integer number (6189841063).

Almost surely, 2^21222312212 is an apocalyptic number.

It is an amenable number.

21222312212 is a deficient number, since it is larger than the sum of its proper divisors (15916734166).

21222312212 is a wasteful number, since it uses less digits than its factorization.

21222312212 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5305578057 (or 5305578055 counting only the distinct ones).

The product of its digits is 384, while the sum is 20.

Adding to 21222312212 its reverse (21221322212), we get a palindrome (42443634424).

The spelling of 21222312212 in words is "twenty-one billion, two hundred twenty-two million, three hundred twelve thousand, two hundred twelve".