218011820 has 48 divisors (see below), whose sum is σ = 496093248. Its totient is φ = 79998720.

The previous prime is 218011813. The next prime is 218011861. The reversal of 218011820 is 28110812.

It is a happy number.

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, 40910 + ... + 45930.

It is an arithmetic number, because the mean of its divisors is an integer number (10335276).

Almost surely, 2^218011820 is an apocalyptic number.

218011820 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 218011820, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (248046624).

218011820 is an abundant number, since it is smaller than the sum of its proper divisors (278081428).

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

218011820 is a wasteful number, since it uses less digits than its factorization.

218011820 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5210 (or 5208 counting only the distinct ones).

The product of its (nonzero) digits is 256, while the sum is 23.

The square root of 218011820 is about 14765.2233305155. The cubic root of 218011820 is about 601.8570426872.

The spelling of 218011820 in words is "two hundred eighteen million, eleven thousand, eight hundred twenty".