21100020009 has 8 divisors (see below), whose sum is σ = 28154989632. Its totient is φ = 14055865200.

The previous prime is 21100020001. The next prime is 21100020023. The reversal of 21100020009 is 90002000112.

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 21100020009 - 2³ = 21100020001 is a prime.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 21100020009.

It is not an unprimeable number, because it can be changed into a prime (21100020001) 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, 2699149 + ... + 2706954.

It is an arithmetic number, because the mean of its divisors is an integer number (3519373704).

Almost surely, 2^21100020009 is an apocalyptic number.

It is an amenable number.

21100020009 is a deficient number, since it is larger than the sum of its proper divisors (7054969623).

21100020009 is a wasteful number, since it uses less digits than its factorization.

21100020009 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5407407.

The product of its (nonzero) digits is 36, while the sum is 15.

The spelling of 21100020009 in words is "twenty-one billion, one hundred million, twenty thousand, nine".