218101811 has 4 divisors (see below), whose sum is σ = 219198000. Its totient is φ = 217005624.

The previous prime is 218101783. The next prime is 218101813. The reversal of 218101811 is 118101812.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 218101811 - 2¹⁸ = 217839667 is a prime.

It is a super-2 number, since 2×218101811² = 95136799922959442, which contains 22 as substring.

It is a Duffinian number.

It is a zygodrome in base 2.

It is not an unprimeable number, because it can be changed into a prime (218101813) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 547796 + ... + 548193.

It is an arithmetic number, because the mean of its divisors is an integer number (54799500).

Almost surely, 2^218101811 is an apocalyptic number.

218101811 is a deficient number, since it is larger than the sum of its proper divisors (1096189).

218101811 is a wasteful number, since it uses less digits than its factorization.

218101811 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1096188.

The product of its (nonzero) digits is 128, while the sum is 23.

The square root of 218101811 is about 14768.2704132881. The cubic root of 218101811 is about 601.9398428867.

Subtracting from 218101811 its reverse (118101812), we obtain a palindrome (99999999).

The spelling of 218101811 in words is "two hundred eighteen million, one hundred one thousand, eight hundred eleven".