218609872 has 20 divisors (see below), whose sum is σ = 456138340. Its totient is φ = 100896768.

The previous prime is 218609869. The next prime is 218609873. The reversal of 218609872 is 278906812.

It can be written as a sum of positive squares in 2 ways, for example, as 130325056 + 88284816 = 11416^2 + 9396^2 .

It is a super-2 number, since 2×218609872² = 95580552271712768, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (218609873) 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 3 ways as a sum of consecutive naturals, for example, 525297 + ... + 525712.

It is an arithmetic number, because the mean of its divisors is an integer number (22806917).

Almost surely, 2^218609872 is an apocalyptic number.

It is an amenable number.

218609872 is an abundant number, since it is smaller than the sum of its proper divisors (237528468).

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

218609872 is a wasteful number, since it uses less digits than its factorization.

218609872 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1051030 (or 1051024 counting only the distinct ones).

The product of its (nonzero) digits is 96768, while the sum is 43.

The square root of 218609872 is about 14785.4615078461. The cubic root of 218609872 is about 602.4068801179.

The spelling of 218609872 in words is "two hundred eighteen million, six hundred nine thousand, eight hundred seventy-two".