20911091111 has 4 divisors (see below), whose sum is σ = 22141155312. Its totient is φ = 19681026912.

The previous prime is 20911091083. The next prime is 20911091143. The reversal of 20911091111 is 11119011902.

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

It is a cyclic number.

It is not a de Polignac number, because 20911091111 - 2¹⁴ = 20911074727 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 (20911091711) 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, 615032075 + ... + 615032108.

It is an arithmetic number, because the mean of its divisors is an integer number (5535288828).

Almost surely, 2^20911091111 is an apocalyptic number.

20911091111 is a deficient number, since it is larger than the sum of its proper divisors (1230064201).

20911091111 is a wasteful number, since it uses less digits than its factorization.

20911091111 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1230064200.

The product of its (nonzero) digits is 162, while the sum is 26.

The spelling of 20911091111 in words is "twenty billion, nine hundred eleven million, ninety-one thousand, one hundred eleven".