20181311 has 2 divisors, whose sum is σ = 20181312. Its totient is φ = 20181310.

The previous prime is 20181247. The next prime is 20181313. The reversal of 20181311 is 11318102.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 20181311 - 2⁶ = 20181247 is a prime.

Together with 20181313, it forms a pair of twin primes.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 20181311.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20181313) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10090655 + 10090656.

It is an arithmetic number, because the mean of its divisors is an integer number (10090656).

Almost surely, 2^20181311 is an apocalyptic number.

20181311 is a deficient number, since it is larger than the sum of its proper divisors (1).

20181311 is an equidigital number, since it uses as much as digits as its factorization.

20181311 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 48, while the sum is 17.

The square root of 20181311 is about 4492.3614057642. The cubic root of 20181311 is about 272.2595516643.

Adding to 20181311 its reverse (11318102), we get a palindrome (31499413).

The spelling of 20181311 in words is "twenty million, one hundred eighty-one thousand, three hundred eleven".