218520138 has 16 divisors (see below), whose sum is σ = 438134976. Its totient is φ = 72657600.

The previous prime is 218520131. The next prime is 218520163. The reversal of 218520138 is 831025812.

218520138 is digitally balanced in base 3, because in such base it contains all the possibile digits an equal number of times.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (218520131) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 43006 + ... + 47817.

It is an arithmetic number, because the mean of its divisors is an integer number (27383436).

Almost surely, 2^218520138 is an apocalyptic number.

218520138 is an abundant number, since it is smaller than the sum of its proper divisors (219614838).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

218520138 is a wasteful number, since it uses less digits than its factorization.

218520138 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 91229.

The product of its (nonzero) digits is 3840, while the sum is 30.

The square root of 218520138 is about 14782.4266614112. The cubic root of 218520138 is about 602.3244444126.

The spelling of 218520138 in words is "two hundred eighteen million, five hundred twenty thousand, one hundred thirty-eight".