20110021209 has 6 divisors (see below), whose sum is σ = 29047808426. Its totient is φ = 13406680800.

The previous prime is 20110021207. The next prime is 20110021213. The reversal of 20110021209 is 90212001102.

It can be written as a sum of positive squares in only one way, i.e., 12288387609 + 7821633600 = 110853^2 + 88440^2 .

It is not a de Polignac number, because 20110021209 - 2¹ = 20110021207 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 20110021191 and 20110021200.

It is not an unprimeable number, because it can be changed into a prime (20110021201) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 1117223392 + ... + 1117223409.

Almost surely, 2^20110021209 is an apocalyptic number.

It is an amenable number.

20110021209 is a deficient number, since it is larger than the sum of its proper divisors (8937787217).

20110021209 is a wasteful number, since it uses less digits than its factorization.

20110021209 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2234446807 (or 2234446804 counting only the distinct ones).

The product of its (nonzero) digits is 72, while the sum is 18.

The spelling of 20110021209 in words is "twenty billion, one hundred ten million, twenty-one thousand, two hundred nine".