21212202009 has 32 divisors (see below), whose sum is σ = 29862936576. Its totient is φ = 13376836800.

The previous prime is 21212201963. The next prime is 21212202041. The reversal of 21212202009 is 90020221212.

It is a happy number.

It is a de Polignac number, because none of the positive numbers 2^k-21212202009 is a prime.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (21212203009) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 774304 + ... + 801230.

It is an arithmetic number, because the mean of its divisors is an integer number (933216768).

Almost surely, 2^21212202009 is an apocalyptic number.

It is an amenable number.

21212202009 is a deficient number, since it is larger than the sum of its proper divisors (8650734567).

21212202009 is a wasteful number, since it uses less digits than its factorization.

21212202009 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 27165.

The product of its (nonzero) digits is 288, while the sum is 21.

The spelling of 21212202009 in words is "twenty-one billion, two hundred twelve million, two hundred two thousand, nine".