218233440 has 168 divisors, whose sum is σ = 773424288. Its totient is φ = 58164480.

The previous prime is 218233409. The next prime is 218233441. The reversal of 218233440 is 44332812.

218233440 is a `hidden beast` number, since 218 + 2 + 3 + 3 + 440 = 666.

It is a hoax number, since the sum of its digits (27) coincides with the sum of the digits of its distinct prime factors.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (218233441) by changing a digit.

It is a polite number, since it can be written in 27 ways as a sum of consecutive naturals, for example, 115705 + ... + 117575.

It is an arithmetic number, because the mean of its divisors is an integer number (4603716).

Almost surely, 2^218233440 is an apocalyptic number.

218233440 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 218233440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (386712144).

218233440 is an abundant number, since it is smaller than the sum of its proper divisors (555190848).

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

218233440 is an equidigital number, since it uses as much as digits as its factorization.

218233440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1904 (or 1881 counting only the distinct ones).

The product of its (nonzero) digits is 4608, while the sum is 27.

The square root of 218233440 is about 14772.7262209790. The cubic root of 218233440 is about 602.0609129579.

The spelling of 218233440 in words is "two hundred eighteen million, two hundred thirty-three thousand, four hundred forty".