218906688 has 448 divisors, whose sum is σ = 835688448. Its totient is φ = 48660480.

The previous prime is 218906687. The next prime is 218906707. The reversal of 218906688 is 886609812.

218906688 is digitally balanced in base 3, because in such base it contains all the possibile digits an equal number of times.

It is a tau number, because it is divible by the number of its divisors (448).

It is a super-2 number, since 2×218906688² = 95840276102258688, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (48).

It is not an unprimeable number, because it can be changed into a prime (218906687) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 3267231 + ... + 3267297.

It is an arithmetic number, because the mean of its divisors is an integer number (1865376).

Almost surely, 2^218906688 is an apocalyptic number.

218906688 is a gapful number since it is divisible by the number (28) 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 218906688, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (417844224).

218906688 is an abundant number, since it is smaller than the sum of its proper divisors (616781760).

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

218906688 is a wasteful number, since it uses less digits than its factorization.

218906688 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 130 (or 120 counting only the distinct ones).

The product of its (nonzero) digits is 331776, while the sum is 48.

The square root of 218906688 is about 14795.4955307350. The cubic root of 218906688 is about 602.6793947069.

The spelling of 218906688 in words is "two hundred eighteen million, nine hundred six thousand, six hundred eighty-eight".