218109645 has 128 divisors (see below), whose sum is σ = 455884800. Its totient is φ = 97977600.

The previous prime is 218109623. The next prime is 218109653. The reversal of 218109645 is 546901812.

218109645 is a `hidden beast` number, since 2 + 1 + 8 + 1 + 0 + 9 + 645 = 666.

It is not a de Polignac number, because 218109645 - 2⁷ = 218109517 is a prime.

It is a super-3 number, since 3×218109645³ (a number of 26 digits) contains 333 as substring.

It is a Smith number, since the sum of its digits (36) coincides with the sum of the digits of its prime factors.

It is a congruent number.

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 127 ways as a sum of consecutive naturals, for example, 1033590 + ... + 1033800.

It is an arithmetic number, because the mean of its divisors is an integer number (3561600).

Almost surely, 2^218109645 is an apocalyptic number.

It is an amenable number.

218109645 is an abundant number, since it is smaller than the sum of its proper divisors (237775155).

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

218109645 is a wasteful number, since it uses less digits than its factorization.

218109645 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 288 (or 282 counting only the distinct ones).

The product of its (nonzero) digits is 17280, while the sum is 36.

The square root of 218109645 is about 14768.5356416945. The cubic root of 218109645 is about 601.9470498271.

The spelling of 218109645 in words is "two hundred eighteen million, one hundred nine thousand, six hundred forty-five".