218532138 has 64 divisors (see below), whose sum is σ = 494778240. Its totient is φ = 63763200.

The previous prime is 218532137. The next prime is 218532151. The reversal of 218532138 is 831235812.

It is a Harshad number since it is a multiple of its sum of digits (33).

It is a junction number, because it is equal to n+sod(n) for n = 218532099 and 218532108.

It is not an unprimeable number, because it can be changed into a prime (218532133) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 265768 + ... + 266588.

It is an arithmetic number, because the mean of its divisors is an integer number (7730910).

Almost surely, 2^218532138 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 218532138, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (247389120).

218532138 is an abundant number, since it is smaller than the sum of its proper divisors (276246102).

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

218532138 is a wasteful number, since it uses less digits than its factorization.

218532138 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 983.

The product of its digits is 11520, while the sum is 33.

The square root of 218532138 is about 14782.8325431901. The cubic root of 218532138 is about 602.3354697291.

The spelling of 218532138 in words is "two hundred eighteen million, five hundred thirty-two thousand, one hundred thirty-eight".