18813911 has 4 divisors (see below), whose sum is σ = 18840312. Its totient is φ = 18787512.

The previous prime is 18813863. The next prime is 18813913. The reversal of 18813911 is 11931881.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 11931881 = 13 ⋅917837.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-18813911 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 (18813913) 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, 12101 + ... + 13566.

It is an arithmetic number, because the mean of its divisors is an integer number (4710078).

Almost surely, 2^18813911 is an apocalyptic number.

18813911 is a deficient number, since it is larger than the sum of its proper divisors (26401).

18813911 is an equidigital number, since it uses as much as digits as its factorization.

18813911 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 26400.

The product of its digits is 1728, while the sum is 32.

The square root of 18813911 is about 4337.5005475504. The cubic root of 18813911 is about 265.9661469723.

The spelling of 18813911 in words is "eighteen million, eight hundred thirteen thousand, nine hundred eleven".