18921011 has 2 divisors, whose sum is σ = 18921012. Its totient is φ = 18921010.

The previous prime is 18920987. The next prime is 18921013. The reversal of 18921011 is 11012981.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 18921011 - 2²² = 14726707 is a prime.

Together with 18921013, it forms a pair of twin primes.

It is a Chen prime.

It is equal to p_1206293 and since 18921011 and 1206293 have the same sum of digits, it is a Honaker prime.

It is not a weakly prime, because it can be changed into another prime (18921013) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9460505 + 9460506.

It is an arithmetic number, because the mean of its divisors is an integer number (9460506).

Almost surely, 2^18921011 is an apocalyptic number.

18921011 is a deficient number, since it is larger than the sum of its proper divisors (1).

18921011 is an equidigital number, since it uses as much as digits as its factorization.

18921011 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 144, while the sum is 23.

The square root of 18921011 is about 4349.8288472077. The cubic root of 18921011 is about 266.4698716450.

Adding to 18921011 its reverse (11012981), we get a palindrome (29933992).

The spelling of 18921011 in words is "eighteen million, nine hundred twenty-one thousand, eleven".