218720400 has 240 divisors, whose sum is σ = 755576640. Its totient is φ = 53913600.

The previous prime is 218720393. The next prime is 218720413. The reversal of 218720400 is 4027812.

It is a tau number, because it is divible by the number of its divisors (240).

It is a super-2 number, since 2×218720400² = 95677226752320000, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (24).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 1208310 + ... + 1208490.

It is an arithmetic number, because the mean of its divisors is an integer number (3148236).

Almost surely, 2^218720400 is an apocalyptic number.

218720400 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 218720400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (377788320).

218720400 is an abundant number, since it is smaller than the sum of its proper divisors (536856240).

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

218720400 is a wasteful number, since it uses less digits than its factorization.

218720400 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 274 (or 263 counting only the distinct ones).

The product of its (nonzero) digits is 896, while the sum is 24.

The square root of 218720400 is about 14789.1987612582. The cubic root of 218720400 is about 602.5083875946.

The spelling of 218720400 in words is "two hundred eighteen million, seven hundred twenty thousand, four hundred".