21001330209 has 8 divisors (see below), whose sum is σ = 28117964512. Its totient is φ = 13942791360.

The previous prime is 21001330187. The next prime is 21001330213. The reversal of 21001330209 is 90203310012.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 21001330209 - 2⁸ = 21001329953 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21001330279) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 14523019 + ... + 14524464.

It is an arithmetic number, because the mean of its divisors is an integer number (3514745564).

Almost surely, 2^21001330209 is an apocalyptic number.

It is an amenable number.

21001330209 is a deficient number, since it is larger than the sum of its proper divisors (7116634303).

21001330209 is a wasteful number, since it uses less digits than its factorization.

21001330209 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 29047727.

The product of its (nonzero) digits is 324, while the sum is 21.

The spelling of 21001330209 in words is "twenty-one billion, one million, three hundred thirty thousand, two hundred nine".