21110021009 has 32 divisors (see below), whose sum is σ = 26620296192. Its totient is φ = 16261560000.

The previous prime is 21110020979. The next prime is 21110021017. The reversal of 21110021009 is 90012001112.

It is not a de Polignac number, because 21110021009 - 2²⁰ = 21108972433 is a prime.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (21110021029) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 6305474 + ... + 6308820.

It is an arithmetic number, because the mean of its divisors is an integer number (831884256).

Almost surely, 2^21110021009 is an apocalyptic number.

It is an amenable number.

21110021009 is a deficient number, since it is larger than the sum of its proper divisors (5510275183).

21110021009 is a wasteful number, since it uses less digits than its factorization.

21110021009 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4277.

The product of its (nonzero) digits is 36, while the sum is 17.

The spelling of 21110021009 in words is "twenty-one billion, one hundred ten million, twenty-one thousand, nine".