20909111 has 4 divisors (see below), whose sum is σ = 21161112. Its totient is φ = 20657112.

The previous prime is 20909089. The next prime is 20909117. The reversal of 20909111 is 11190902.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 11190902 = 2 ⋅5595451.

It is a cyclic number.

It is not a de Polignac number, because 20909111 - 2¹⁴ = 20892727 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 (20909117) 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, 125876 + ... + 126041.

It is an arithmetic number, because the mean of its divisors is an integer number (5290278).

Almost surely, 2^20909111 is an apocalyptic number.

20909111 is a deficient number, since it is larger than the sum of its proper divisors (252001).

20909111 is an equidigital number, since it uses as much as digits as its factorization.

20909111 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 252000.

The product of its (nonzero) digits is 162, while the sum is 23.

The square root of 20909111 is about 4572.6481386610. The cubic root of 20909111 is about 275.4938168557.

The spelling of 20909111 in words is "twenty million, nine hundred nine thousand, one hundred eleven".