21221100999 has 12 divisors (see below), whose sum is σ = 35031658896. Its totient is φ = 12126343392.

The previous prime is 21221100997. The next prime is 21221101019. The reversal of 21221100999 is 99900112212.

It is not a de Polignac number, because 21221100999 - 2¹ = 21221100997 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21221100997) 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 11 ways as a sum of consecutive naturals, for example, 168421374 + ... + 168421499.

It is an arithmetic number, because the mean of its divisors is an integer number (2919304908).

Almost surely, 2^21221100999 is an apocalyptic number.

21221100999 is a deficient number, since it is larger than the sum of its proper divisors (13810557897).

21221100999 is a wasteful number, since it uses less digits than its factorization.

21221100999 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 336842886 (or 336842883 counting only the distinct ones).

The product of its (nonzero) digits is 5832, while the sum is 36.

The spelling of 21221100999 in words is "twenty-one billion, two hundred twenty-one million, one hundred thousand, nine hundred ninety-nine".