21000122212 has 6 divisors (see below), whose sum is σ = 36750213878. Its totient is φ = 10500061104.

The previous prime is 21000122201. The next prime is 21000122233. The reversal of 21000122212 is 21222100012.

It is a happy number.

It can be written as a sum of positive squares in only one way, i.e., 20225390656 + 774731556 = 142216^2 + 27834^2 .

It is a junction number, because it is equal to n+sod(n) for n = 21000122192 and 21000122201.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2625015273 + ... + 2625015280.

Almost surely, 2^21000122212 is an apocalyptic number.

It is an amenable number.

21000122212 is a deficient number, since it is larger than the sum of its proper divisors (15750091666).

21000122212 is a wasteful number, since it uses less digits than its factorization.

21000122212 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5250030557 (or 5250030555 counting only the distinct ones).

The product of its (nonzero) digits is 32, while the sum is 13.

Adding to 21000122212 its reverse (21222100012), we get a palindrome (42222222224).

The spelling of 21000122212 in words is "twenty-one billion, one hundred twenty-two thousand, two hundred twelve".