18938811 has 4 divisors (see below), whose sum is σ = 25251752. Its totient is φ = 12625872.

The previous prime is 18938809. The next prime is 18938831. The reversal of 18938811 is 11883981.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 11883981 = 3 ⋅3961327.

It is not a de Polignac number, because 18938811 - 2¹ = 18938809 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 18938811.

It is not an unprimeable number, because it can be changed into a prime (18938831) 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, 3156466 + ... + 3156471.

It is an arithmetic number, because the mean of its divisors is an integer number (6312938).

Almost surely, 2^18938811 is an apocalyptic number.

18938811 is a deficient number, since it is larger than the sum of its proper divisors (6312941).

18938811 is an equidigital number, since it uses as much as digits as its factorization.

18938811 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6312940.

The product of its digits is 13824, while the sum is 39.

The square root of 18938811 is about 4351.8744237397. The cubic root of 18938811 is about 266.5534062424.

The spelling of 18938811 in words is "eighteen million, nine hundred thirty-eight thousand, eight hundred eleven".