21110212009 has 16 divisors (see below), whose sum is σ = 23358475008. Its totient is φ = 18993445632.

The previous prime is 21110212003. The next prime is 21110212099. The reversal of 21110212009 is 90021201112.

It is a happy number.

It is a cyclic number.

It is not a de Polignac number, because 21110212009 - 2¹¹ = 21110209961 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21110212003) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 272862 + ... + 341575.

It is an arithmetic number, because the mean of its divisors is an integer number (1459904688).

Almost surely, 2^21110212009 is an apocalyptic number.

It is an amenable number.

21110212009 is a deficient number, since it is larger than the sum of its proper divisors (2248262999).

21110212009 is a wasteful number, since it uses less digits than its factorization.

21110212009 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 614544.

The product of its (nonzero) digits is 72, while the sum is 19.

The spelling of 21110212009 in words is "twenty-one billion, one hundred ten million, two hundred twelve thousand, nine".