218989440 has 512 divisors, whose sum is σ = 881280000. Its totient is φ = 51093504.

The previous prime is 218989399. The next prime is 218989447. The reversal of 218989440 is 44989812.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (218989447) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 7551346 + ... + 7551374.

It is an arithmetic number, because the mean of its divisors is an integer number (1721250).

Almost surely, 2^218989440 is an apocalyptic number.

218989440 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 218989440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (440640000).

218989440 is an abundant number, since it is smaller than the sum of its proper divisors (662290560).

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

218989440 is a wasteful number, since it uses less digits than its factorization.

218989440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 99 (or 81 counting only the distinct ones).

The product of its (nonzero) digits is 165888, while the sum is 45.

The square root of 218989440 is about 14798.2917933118. The cubic root of 218989440 is about 602.7553275814.

The spelling of 218989440 in words is "two hundred eighteen million, nine hundred eighty-nine thousand, four hundred forty".