21002100209 has 8 divisors (see below), whose sum is σ = 21223375488. Its totient is φ = 20780922240.

The previous prime is 21002100199. The next prime is 21002100221. The reversal of 21002100209 is 90200120012.

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

It is a cyclic number.

It is not a de Polignac number, because 21002100209 - 2¹² = 21002096113 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21002100269) 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, 460004 + ... + 503594.

It is an arithmetic number, because the mean of its divisors is an integer number (2652921936).

Almost surely, 2^21002100209 is an apocalyptic number.

It is an amenable number.

21002100209 is a deficient number, since it is larger than the sum of its proper divisors (221275279).

21002100209 is an equidigital number, since it uses as much as digits as its factorization.

21002100209 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 48655.

The product of its (nonzero) digits is 72, while the sum is 17.

The spelling of 21002100209 in words is "twenty-one billion, two million, one hundred thousand, two hundred nine".