218605640 has 128 divisors (see below), whose sum is σ = 573696000. Its totient is φ = 74131200.

The previous prime is 218605633. The next prime is 218605661. The reversal of 218605640 is 46506812.

It is a junction number, because it is equal to n+sod(n) for n = 218605597 and 218605606.

It is an unprimeable number.

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, 660275 + ... + 660605.

It is an arithmetic number, because the mean of its divisors is an integer number (4482000).

Almost surely, 2^218605640 is an apocalyptic number.

218605640 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 218605640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (286848000).

218605640 is an abundant number, since it is smaller than the sum of its proper divisors (355090360).

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

218605640 is a wasteful number, since it uses less digits than its factorization.

218605640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 451 (or 447 counting only the distinct ones).

The product of its (nonzero) digits is 11520, while the sum is 32.

The square root of 218605640 is about 14785.3183935957. The cubic root of 218605640 is about 602.4029928242.

The spelling of 218605640 in words is "two hundred eighteen million, six hundred five thousand, six hundred forty".