211221009999 has 12 divisors (see below), whose sum is σ = 305286654400. Its totient is φ = 140726480544.

The previous prime is 211221009953. The next prime is 211221010003. The reversal of 211221009999 is 999900122112.

211221009999 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 211221009999 - 2¹¹ = 211221007951 is a prime.

It is a super-2 number, since 2×211221009999² (a number of 23 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (211221009949) by changing a digit.

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 in 11 ways as a sum of consecutive naturals, for example, 7278559 + ... + 7307520.

Almost surely, 2^211221009999 is an apocalyptic number.

211221009999 is a deficient number, since it is larger than the sum of its proper divisors (94065644401).

211221009999 is a wasteful number, since it uses less digits than its factorization.

211221009999 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 14587694 (or 14587691 counting only the distinct ones).

The product of its (nonzero) digits is 52488, while the sum is 45.

The spelling of 211221009999 in words is "two hundred eleven billion, two hundred twenty-one million, nine thousand, nine hundred ninety-nine".