21106940209 has 8 divisors (see below), whose sum is σ = 21946848768. Its totient is φ = 20276971680.

The previous prime is 21106940171. The next prime is 21106940213. The reversal of 21106940209 is 90204960112.

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 21106940209 - 2¹⁵ = 21106907441 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21106947209) 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, 2480677 + ... + 2489170.

It is an arithmetic number, because the mean of its divisors is an integer number (2743356096).

Almost surely, 2^21106940209 is an apocalyptic number.

It is an amenable number.

21106940209 is a deficient number, since it is larger than the sum of its proper divisors (839908559).

21106940209 is a wasteful number, since it uses less digits than its factorization.

21106940209 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4970015.

The product of its (nonzero) digits is 7776, while the sum is 34.

The spelling of 21106940209 in words is "twenty-one billion, one hundred six million, nine hundred forty thousand, two hundred nine".