21221211212 has 12 divisors (see below), whose sum is σ = 37158030840. Its totient is φ = 10604630976.

The previous prime is 21221211173. The next prime is 21221211217. The reversal of 21221211212 is 21211212212.

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 (21221211217) 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, 1485662 + ... + 1499877.

It is an arithmetic number, because the mean of its divisors is an integer number (3096502570).

Almost surely, 2^21221211212 is an apocalyptic number.

It is an amenable number.

21221211212 is a deficient number, since it is larger than the sum of its proper divisors (15936819628).

21221211212 is a wasteful number, since it uses less digits than its factorization.

21221211212 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2987320 (or 2987318 counting only the distinct ones).

The product of its digits is 64, while the sum is 17.

Adding to 21221211212 its reverse (21211212212), we get a palindrome (42432423424).

It can be divided in two parts, 212 and 21211212, that multiplied together give a palindrome (4496776944).

The spelling of 21221211212 in words is "twenty-one billion, two hundred twenty-one million, two hundred eleven thousand, two hundred twelve".