18216240 has 120 divisors (see below), whose sum is σ = 65732400. Its totient is φ = 4161024.

The previous prime is 18216229. The next prime is 18216241. The reversal of 18216240 is 4261281.

It is a tau number, because it is divible by the number of its divisors (120).

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

It is a self number, because there is not a number n which added to its sum of digits gives 18216240.

It is not an unprimeable number, because it can be changed into a prime (18216241) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 10986 + ... + 12534.

It is an arithmetic number, because the mean of its divisors is an integer number (547770).

Almost surely, 2^18216240 is an apocalyptic number.

18216240 is a gapful number since it is divisible by the number (10) 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 18216240, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (32866200).

18216240 is an abundant number, since it is smaller than the sum of its proper divisors (47516160).

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

18216240 is a wasteful number, since it uses less digits than its factorization.

18216240 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1579 (or 1566 counting only the distinct ones).

The product of its (nonzero) digits is 768, while the sum is 24.

The square root of 18216240 is about 4268.0487344921. The cubic root of 18216240 is about 263.1194260681.

The spelling of 18216240 in words is "eighteen million, two hundred sixteen thousand, two hundred forty".