218540905 has 16 divisors (see below), whose sum is σ = 286380864. Its totient is φ = 158777280.

The previous prime is 218540887. The next prime is 218540977. The reversal of 218540905 is 509045812.

218540905 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 218540905 - 2²⁷ = 84323177 is a prime.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 91942 + ... + 94288.

It is an arithmetic number, because the mean of its divisors is an integer number (17898804).

Almost surely, 2^218540905 is an apocalyptic number.

It is an amenable number.

218540905 is a deficient number, since it is larger than the sum of its proper divisors (67839959).

218540905 is a wasteful number, since it uses less digits than its factorization.

218540905 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4056.

The product of its (nonzero) digits is 14400, while the sum is 34.

The square root of 218540905 is about 14783.1290666083. The cubic root of 218540905 is about 602.3435243864.

Subtracting from 218540905 its sum of digits (34), we obtain a triangular number (218540871 = T₂₀₉₀₆).

The spelling of 218540905 in words is "two hundred eighteen million, five hundred forty thousand, nine hundred five".