18820911 has 4 divisors (see below), whose sum is σ = 25094552. Its totient is φ = 12547272.

The previous prime is 18820909. The next prime is 18820931. The reversal of 18820911 is 11902881.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 11902881 = 3 ⋅3967627.

It is not a de Polignac number, because 18820911 - 2¹ = 18820909 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 (18820931) 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, 3136816 + ... + 3136821.

It is an arithmetic number, because the mean of its divisors is an integer number (6273638).

Almost surely, 2^18820911 is an apocalyptic number.

18820911 is a deficient number, since it is larger than the sum of its proper divisors (6273641).

18820911 is an equidigital number, since it uses as much as digits as its factorization.

18820911 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6273640.

The product of its (nonzero) digits is 1152, while the sum is 30.

The square root of 18820911 is about 4338.3073888327. The cubic root of 18820911 is about 265.9991284574. Note that the first 3 decimals are identical.

The spelling of 18820911 in words is "eighteen million, eight hundred twenty thousand, nine hundred eleven".