21212012099 has 4 divisors (see below), whose sum is σ = 21250095264. Its totient is φ = 21173928936.

The previous prime is 21212012069. The next prime is 21212012141. The reversal of 21212012099 is 99021021212.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 21212012099 - 2¹² = 21212008003 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21212012069) 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 3 ways as a sum of consecutive naturals, for example, 19040747 + ... + 19041860.

It is an arithmetic number, because the mean of its divisors is an integer number (5312523816).

Almost surely, 2^21212012099 is an apocalyptic number.

21212012099 is a deficient number, since it is larger than the sum of its proper divisors (38083165).

21212012099 is an equidigital number, since it uses as much as digits as its factorization.

21212012099 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 38083164.

The product of its (nonzero) digits is 1296, while the sum is 29.

The spelling of 21212012099 in words is "twenty-one billion, two hundred twelve million, twelve thousand, ninety-nine".