218881386 has 128 divisors (see below), whose sum is σ = 539136000. Its totient is φ = 65596608.

The previous prime is 218881343. The next prime is 218881391. The reversal of 218881386 is 683188812.

It is a super-2 number, since 2×218881386² = 95818122274561992, which contains 22 as substring.

It is a Smith number, since the sum of its digits (45) coincides with the sum of the digits of its prime factors.

It is an unprimeable number.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 2125011 + ... + 2125113.

It is an arithmetic number, because the mean of its divisors is an integer number (4212000).

Almost surely, 2^218881386 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 218881386, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (269568000).

218881386 is an abundant number, since it is smaller than the sum of its proper divisors (320254614).

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

218881386 is a wasteful number, since it uses less digits than its factorization.

218881386 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 225 (or 219 counting only the distinct ones).

The product of its digits is 147456, while the sum is 45.

The square root of 218881386 is about 14794.6404484867. The cubic root of 218881386 is about 602.6561738820.

The spelling of 218881386 in words is "two hundred eighteen million, eight hundred eighty-one thousand, three hundred eighty-six".