218221605 has 48 divisors (see below), whose sum is σ = 457726464. Its totient is φ = 93888000.

The previous prime is 218221573. The next prime is 218221651. The reversal of 218221605 is 506122812.

It is a happy number.

It is not a de Polignac number, because 218221605 - 2⁵ = 218221573 is a prime.

It is a Curzon number.

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 47 ways as a sum of consecutive naturals, for example, 15021 + ... + 25730.

It is an arithmetic number, because the mean of its divisors is an integer number (9535968).

Almost surely, 2^218221605 is an apocalyptic number.

It is an amenable number.

218221605 is an abundant number, since it is smaller than the sum of its proper divisors (239504859).

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

218221605 is a wasteful number, since it uses less digits than its factorization.

218221605 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 40786 (or 40783 counting only the distinct ones).

The product of its (nonzero) digits is 1920, while the sum is 27.

The square root of 218221605 is about 14772.3256462887. The cubic root of 218221605 is about 602.0500293223.

The spelling of 218221605 in words is "two hundred eighteen million, two hundred twenty-one thousand, six hundred five".