18993211 has 2 divisors, whose sum is σ = 18993212. Its totient is φ = 18993210.

The previous prime is 18993203. The next prime is 18993251. The reversal of 18993211 is 11239981.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 18993211 - 2³ = 18993203 is a prime.

It is not a weakly prime, because it can be changed into another prime (18993251) 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, 9496605 + 9496606.

It is an arithmetic number, because the mean of its divisors is an integer number (9496606).

Almost surely, 2^18993211 is an apocalyptic number.

18993211 is a deficient number, since it is larger than the sum of its proper divisors (1).

18993211 is an equidigital number, since it uses as much as digits as its factorization.

18993211 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 3888, while the sum is 34.

The square root of 18993211 is about 4358.1201222545. The cubic root of 18993211 is about 266.8083790180.

The spelling of 18993211 in words is "eighteen million, nine hundred ninety-three thousand, two hundred eleven".