21212122001 has 24 divisors (see below), whose sum is σ = 25158734784. Its totient is φ = 17826113760.

The previous prime is 21212121971. The next prime is 21212122027. The reversal of 21212122001 is 10022121212.

It is not a de Polignac number, because 21212122001 - 2⁶ = 21212121937 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (21212122051) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 6290846 + ... + 6294216.

It is an arithmetic number, because the mean of its divisors is an integer number (1048280616).

Almost surely, 2^21212122001 is an apocalyptic number.

It is an amenable number.

21212122001 is a deficient number, since it is larger than the sum of its proper divisors (3946612783).

21212122001 is a wasteful number, since it uses less digits than its factorization.

21212122001 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5861 (or 5854 counting only the distinct ones).

The product of its (nonzero) digits is 32, while the sum is 14.

Adding to 21212122001 its reverse (10022121212), we get a palindrome (31234243213).

The spelling of 21212122001 in words is "twenty-one billion, two hundred twelve million, one hundred twenty-two thousand, one".