21002120211009 has 32 divisors (see below), whose sum is σ = 32056850452480. Its totient is φ = 11981106513792.

The previous prime is 21002120211001. The next prime is 21002120211013. The reversal of 21002120211009 is 90011202120012.

It is not a de Polignac number, because 21002120211009 - 2³ = 21002120211001 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (21).

It is not an unprimeable number, because it can be changed into a prime (21002120211001) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 279271917 + ... + 279347109.

It is an arithmetic number, because the mean of its divisors is an integer number (1001776576640).

Almost surely, 2^{21002120211009} is an apocalyptic number.

It is an amenable number.

21002120211009 is a deficient number, since it is larger than the sum of its proper divisors (11054730241471).

21002120211009 is a wasteful number, since it uses less digits than its factorization.

21002120211009 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 97309.

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

The spelling of 21002120211009 in words is "twenty-one trillion, two billion, one hundred twenty million, two hundred eleven thousand, nine".