218540505 has 8 divisors (see below), whose sum is σ = 349664832. Its totient is φ = 116554928.

The previous prime is 218540477. The next prime is 218540519. The reversal of 218540505 is 505045812.

218540505 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 218540505 - 2⁵ = 218540473 is a prime.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 7284669 + ... + 7284698.

It is an arithmetic number, because the mean of its divisors is an integer number (43708104).

Almost surely, 2^218540505 is an apocalyptic number.

It is an amenable number.

218540505 is a deficient number, since it is larger than the sum of its proper divisors (131124327).

218540505 is a wasteful number, since it uses less digits than its factorization.

218540505 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 14569375.

The product of its (nonzero) digits is 8000, while the sum is 30.

The square root of 218540505 is about 14783.1155376666. The cubic root of 218540505 is about 602.3431568922.

The spelling of 218540505 in words is "two hundred eighteen million, five hundred forty thousand, five hundred five".