21001222212 has 96 divisors (see below), whose sum is σ = 50946465024. Its totient is φ = 6728601600.

The previous prime is 21001222189. The next prime is 21001222219. The reversal of 21001222212 is 21222210012.

It is a junction number, because it is equal to n+sod(n) for n = 21001222191 and 21001222200.

It is not an unprimeable number, because it can be changed into a prime (21001222219) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 10061833 + ... + 10063919.

It is an arithmetic number, because the mean of its divisors is an integer number (530692344).

Almost surely, 2^21001222212 is an apocalyptic number.

It is an amenable number.

21001222212 is an abundant number, since it is smaller than the sum of its proper divisors (29945242812).

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

21001222212 is a wasteful number, since it uses less digits than its factorization.

21001222212 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2429 (or 2427 counting only the distinct ones).

The product of its (nonzero) digits is 64, while the sum is 15.

Adding to 21001222212 its reverse (21222210012), we get a palindrome (42223432224).

The spelling of 21001222212 in words is "twenty-one billion, one million, two hundred twenty-two thousand, two hundred twelve".