218533840 has 160 divisors (see below), whose sum is σ = 610675200. Its totient is φ = 71165952.

The previous prime is 218533837. The next prime is 218533841. The reversal of 218533840 is 48335812.

It is a happy number.

It is a junction number, because it is equal to n+sod(n) for n = 218533796 and 218533805.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (218533841) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 1098061 + ... + 1098259.

It is an arithmetic number, because the mean of its divisors is an integer number (3816720).

Almost surely, 2^218533840 is an apocalyptic number.

218533840 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 218533840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (305337600).

218533840 is an abundant number, since it is smaller than the sum of its proper divisors (392141360).

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

218533840 is a wasteful number, since it uses less digits than its factorization.

218533840 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 309 (or 303 counting only the distinct ones).

The product of its (nonzero) digits is 23040, while the sum is 34.

The square root of 218533840 is about 14782.8901098534. The cubic root of 218533840 is about 602.3370334538.

The spelling of 218533840 in words is "two hundred eighteen million, five hundred thirty-three thousand, eight hundred forty".