20212109 has 4 divisors (see below), whose sum is σ = 20329116. Its totient is φ = 20095104.

The previous prime is 20212103. The next prime is 20212111. The reversal of 20212109 is 90121202.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 9746884 + 10465225 = 3122^2 + 3235^2 .

It is a cyclic number.

It is not a de Polignac number, because 20212109 - 2¹⁶ = 20146573 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20212103) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 58244 + ... + 58589.

It is an arithmetic number, because the mean of its divisors is an integer number (5082279).

Almost surely, 2^20212109 is an apocalyptic number.

It is an amenable number.

20212109 is a deficient number, since it is larger than the sum of its proper divisors (117007).

20212109 is a wasteful number, since it uses less digits than its factorization.

20212109 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 117006.

The product of its (nonzero) digits is 72, while the sum is 17.

The square root of 20212109 is about 4495.7879175958. The cubic root of 20212109 is about 272.3979765649.

The spelling of 20212109 in words is "twenty million, two hundred twelve thousand, one hundred nine".