218593221 has 16 divisors (see below), whose sum is σ = 363376128. Its totient is φ = 113554800.

The previous prime is 218593163. The next prime is 218593223. The reversal of 218593221 is 122395812.

It is a happy number.

It is not a de Polignac number, because 218593221 - 2⁷ = 218593093 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (33).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (218593223) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 472915 + ... + 473376.

It is an arithmetic number, because the mean of its divisors is an integer number (22711008).

Almost surely, 2^218593221 is an apocalyptic number.

218593221 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

It is an amenable number.

218593221 is a deficient number, since it is larger than the sum of its proper divisors (144782907).

218593221 is a wasteful number, since it uses less digits than its factorization.

218593221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 946312.

The product of its digits is 8640, while the sum is 33.

The square root of 218593221 is about 14784.8984102022. The cubic root of 218593221 is about 602.3915850910.

The spelling of 218593221 in words is "two hundred eighteen million, five hundred ninety-three thousand, two hundred twenty-one".