21000120212109 has 16 divisors (see below), whose sum is σ = 28168126922880. Its totient is φ = 13916098613760.

The previous prime is 21000120212089. The next prime is 21000120212111. The reversal of 21000120212109 is 90121202100012.

It is not a de Polignac number, because 21000120212109 - 2⁹ = 21000120211597 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21000120212129) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 66560289 + ... + 66875049.

It is an arithmetic number, because the mean of its divisors is an integer number (1760507932680).

Almost surely, 2^{21000120212109} is an apocalyptic number.

It is an amenable number.

21000120212109 is a deficient number, since it is larger than the sum of its proper divisors (7168006710771).

21000120212109 is a wasteful number, since it uses less digits than its factorization.

21000120212109 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 448100.

The product of its (nonzero) digits is 144, while the sum is 21.

The spelling of 21000120212109 in words is "twenty-one trillion, one hundred twenty million, two hundred twelve thousand, one hundred nine".