18213811 has 16 divisors (see below), whose sum is σ = 23240448. Its totient is φ = 13860000.

The previous prime is 18213803. The next prime is 18213823. The reversal of 18213811 is 11831281.

It is not a de Polignac number, because 18213811 - 2³ = 18213803 is a prime.

It is a super-2 number, since 2×18213811² = 663485822287442, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (18213211) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 561 + ... + 6061.

It is an arithmetic number, because the mean of its divisors is an integer number (1452528).

Almost surely, 2^18213811 is an apocalyptic number.

18213811 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

18213811 is a deficient number, since it is larger than the sum of its proper divisors (5026637).

18213811 is a wasteful number, since it uses less digits than its factorization.

18213811 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5562.

The product of its digits is 384, while the sum is 25.

The square root of 18213811 is about 4267.7641687422. The cubic root of 18213811 is about 263.1077305427.

The spelling of 18213811 in words is "eighteen million, two hundred thirteen thousand, eight hundred eleven".