21212211001212 has 72 divisors (see below), whose sum is σ = 66850604376192. Its totient is φ = 5509665194400.

The previous prime is 21212211001211. The next prime is 21212211001237. The reversal of 21212211001212 is 21210011221212.

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21212211001211) 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, 3826153614 + ... + 3826159157.

It is an arithmetic number, because the mean of its divisors is an integer number (928480616336).

Almost surely, 2^{21212211001212} is an apocalyptic number.

21212211001212 is a gapful number since it is divisible by the number (22) formed by its first and last digit.

It is an amenable number.

21212211001212 is an abundant number, since it is smaller than the sum of its proper divisors (45638393374980).

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

21212211001212 is a wasteful number, since it uses less digits than its factorization.

21212211001212 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7652312799 (or 7652312794 counting only the distinct ones).

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

Adding to 21212211001212 its reverse (21210011221212), we get a palindrome (42422222222424).

The spelling of 21212211001212 in words is "twenty-one trillion, two hundred twelve billion, two hundred eleven million, one thousand, two hundred twelve".