218020404 has 144 divisors (see below), whose sum is σ = 632475648. Its totient is φ = 58315488.

The previous prime is 218020379. The next prime is 218020417. The reversal of 218020404 is 404020812.

It is a Harshad number since it is a multiple of its sum of digits (21).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 4638709 + ... + 4638755.

It is an arithmetic number, because the mean of its divisors is an integer number (4392192).

Almost surely, 2^218020404 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 218020404, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (316237824).

218020404 is an abundant number, since it is smaller than the sum of its proper divisors (414455244).

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

218020404 is an equidigital number, since it uses as much as digits as its factorization.

218020404 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 112 (or 82 counting only the distinct ones).

The product of its (nonzero) digits is 512, while the sum is 21.

The square root of 218020404 is about 14765.5140106940. The cubic root of 218020404 is about 601.8649417590.

It can be divided in two parts, 21 and 8020404, that multiplied together give a square (168428484 = 12978²).

The spelling of 218020404 in words is "two hundred eighteen million, twenty thousand, four hundred four".